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                                                                  EXHIBIT 10.1.8


                                PLEDGE AGREEMENT


                  THIS PLEDGE AGREEMENT (this "AGREEMENT"), dated as of June 29,
2001, is made by PATTERSON-UTI ENERGY, INC., a Delaware corporation ("PARENT"),
PATTERSON (GP) LLC, a Delaware limited liability company ("PATTERSON GP"),
PATTERSON (LP) LLC, a Delaware limited liability company ("PATTERSON LP"),
PATTERSON-UTI DRILLING COMPANY LP, LLLP, a Delaware limited liability limited
partnership ("PUDC"), and PATTERSON (GP2) LLC, a Delaware limited liability
company ("PATTERSON GP2") (Parent, Patterson GP, Patterson LP, PUDC and
Patterson GP2 are referred to herein individually as "PLEDGOR" and collectively
as the "PLEDGORS") in favor of THE CIT GROUP/BUSINESS CREDIT, INC., a New York
corporation having an office located at 1211 Avenue of the Americas, New York,
New York 10026 ("CITBC"), as Agent, pledgee, assignee and secured party (in any
and all such capacities and together with any successors in such capacities,
"AGENT") for the benefit of the Lenders (as defined below).

                                    RECITALS:

         A. The ownership interests owned by each Pledgor which are being
pledged hereunder are as follows: (1) Parent owns all of the issued and
outstanding capital stock of UTICO, Inc., a Delaware corporation ("Holding") and
a 100% membership interest in Patterson LP and Patterson GP; (2) Patterson LP
owns a 99% limited partnership interest in PUDC, LONE STAR MUD LP, LLLP, a
Delaware limited liability limited partnership, ("LSM"), AMBAR DRILLING FLUIDS
LP, LLLP, a Delaware limited liability limited partnership ("ADF"), patterson
petroleum lp, lllp, a Delaware limited liability limited partnership ("PPLP"),
and patterson petroleum trading company lp, lllp, a Delaware limited liability
limited partnership ("PPTC"); (3) Patterson GP owns a 1% general partnership
interest in PUDC, LSM, ADF, PPLP and PPTC; (4) PUDC owns a 99% limited
partnership interest in PATTERSON-UTI DRILLING COMPANY SOUTH LP, LLLP, a
Delaware limited liability limited partnership ("PUDCS") and PATTERSON-UTI
DRILLING COMPANY WEST LP, LLLP, a Delaware limited liability limited partnership
("PUDCW") and a 100% membership interest in PATTERSON GP2; and (5) Patterson GP2
owns a 1% general partnership interest in PUDCS and PUDCW.

         B. Each Pledgor is the legal, record and beneficial owner of the
Pledged Collateral (as defined below) pledged by it pursuant to this Agreement.

         C. UTI Drilling, L.P., a Texas limited partnership ("UTI"), Universal
Well Services, Inc., a Delaware corporation ("UWSI"), UTI Management Services,
L.P., a Texas limited partnership ("UTIMS"), Norton Drilling l.p., a Delaware
limited partnership, successor in interest by merger to Norton Drilling Company
("NDLP"), Suits Drilling Company, an Oklahoma corporation ("SDC"), PUDC, PUDCS,
PUDCW, LSM,

                                                            UTI-PLEDGE AGREEMENT

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and ADF (collectively, the "Borrowers") have entered into the Loan and Security
Agreement dated as of November 22, 1999 (as amended and modified or supplemented
from time to time, the "Loan Agreement") with Agent and the Lenders named
therein and from time to time parties thereto (collectively, the "Lenders"),
pursuant to which, among other things, the Lenders have agreed to provide
certain credit accommodations to or for the benefit of the Borrowers and each
Pledgor has agreed to be liable to the Agent and the Lenders in respect of such
credit accommodations. Capitalized terms used herein and not defined shall have
the meaning assigned to such terms in the Loan Agreement.

         D. Each of the Pledgors has represented to the Agent and the Lenders
that each Pledgor will receive substantial benefit from the performance of the
Loan Agreement, and each Pledgor has agreed to grant to the Agent, liens and
security interests in the Pledged Collateral owned by it to secure the Secured
Obligations (as hereinafter defined).

         E. It is a condition to the obligations of the Lenders to continue to
make the Loans under the Loan Agreement and to issue Letters of Credit that the
Pledgors execute and deliver the applicable Loan Documents, including this
Agreement.

                                   AGREEMENT:

         NOW, THEREFORE, in consideration of the foregoing premises and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, each Pledgor and Agent hereby agree as follows:

Section 1. Pledge. As collateral security for the payment and performance when
due of all of the Secured Obligations, each Pledgor, jointly and severally,
hereby pledges, assigns, transfers and grants to Agent for its benefit and the
benefit of the Lenders, a continuing first priority security interest in and to
all of the right, title and interest of such Pledgor in, to and under the
following property, whether now existing or hereafter acquired (collectively,
the "PLEDGED COLLATERAL"):

                  (a) all of the issued and outstanding shares of capital stock
         of Holding described on Schedule A hereto (the "PLEDGED STOCK") (which
         are and shall, subject to Section 4(b) hereof, remain at all times
         until this Agreement terminates, certificated shares), including the
         certificates representing the Pledged Stock and any interest of Parent
         in the entries on the books of any financial intermediary pertaining to
         the Pledged Stock;

                  (b) all additional shares of capital stock of any issuer of
         the Pledged Stock from time to time acquired by any Pledgor in any
         manner (which are and shall, subject to Section 4(b) hereof, remain at
         all times until this Agreement terminates, certificated shares) (which
         shares shall, upon acquisition, be deemed to be part of the Pledged
         Stock), including the certificates representing such additional shares
         and any interest of any Pledgor in the entries on the books of any
         financial intermediary pertaining to such additional shares;

                                                            UTI-PLEDGE AGREEMENT

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                  (c) all partnership interests in (i) PUDC, LSM, ADF, PPLP and
         PPTC owned by Patterson LP and Patterson GP, and (ii) PUDCW and PUDCS
         owned by PUDC and Patterson-GP2, together with all rights, privileges,
         authority and powers of such Pledgors in and to PUDC, LSM, ADF, PPLP,
         PPTC, PPDCW and PPDCS (collectively, the "Partnerships") or under the
         Agreements of Limited Partnership of the Partnerships (the "PARTNERSHIP
         AGREEMENTS") (collectively, the "INITIAL PLEDGED PARTNERSHIP
         INTERESTS"), and the certificates, instruments and agreements, if any,
         representing the Initial Pledged Partnership Interests;

                  (d) (i) all of the membership interests (1) of Patterson GP
                  and Patterson LP owned by Parent and (2) of Patterson GP2
                  owned by PUDC (the "Initial Pledged Membership Interests");

                  (ii) all limited liability company membership interests and
                  all other ownership interests in any issuer which such
                  Pledgors shall, from time to time, become entitled to receive
                  or shall receive pursuant to subsection (d)(iii) hereof, all
                  certificates, if any, representing any such membership
                  interests, all options and other rights, contractual or
                  otherwise, at any time existing with respect to such
                  membership interests, and all dividends, cash, instruments and
                  other property now or hereafter received, receivable or
                  otherwise distributed in respect of or in exchange for any or
                  all of such membership interests; and

                  (iii) all rights, privileges, authority and powers of such
                  Pledgors under all operating agreements, certificates, and
                  other agreements of Patterson GP, Patterson LP and Patterson
                  GP2 (being herein called the "LLC Agreements");

                  (e) all options, warrants, rights, agreements, additional
         partnership interests or other interests relating to any Borrower,
         Pledgor or any Guarantor (as defined in the Loan Agreement)
         (collectively, the "ADDITIONAL INTERESTS"; and, collectively with the
         Initial Pledged Partnership Interests and the Initial Pledged
         Membership Interests, the "PLEDGED INTEREST"; and, collectively with
         the Pledged Stock, the "PLEDGED SECURITIES") from time to time acquired
         by the Pledgor in any manner and the certificates, instruments and
         agreements, if any, representing the Additional Interests;

                  (f) all intercompany notes now owned or held by any Pledgor
         and from time to time acquired by any Pledgor in any way, including the
         intercompany notes described on Schedule B hereto (collectively, the
         "INTERCOMPANY NOTES") and all certificates or instruments evidencing
         such Intercompany Notes and all proceeds thereof, all accessions
         thereto and substitutions therefor;

                  (g) all dividends, cash, options, warrants, rights,
         instruments, distributions, returns of capital, income, profits and
         other property, interests or proceeds from time to time received,
         receivable or otherwise distributed to any Pledgor in respect of or in
         exchange for any or all of the Pledged Securities or Intercompany Notes
         (collectively, "DISTRIBUTIONS"); and

                                                            UTI-PLEDGE AGREEMENT

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                  (h) all proceeds (as defined under the Uniform Commercial Code
         as in effect in any relevant jurisdiction (the "CODE") or under other
         relevant law) of any of the foregoing, and in any event, including,
         without limitation, any and all (i) proceeds of any insurance (except
         liability insurance payments in which no Pledgor has any interest made
         to a Person exclusively entitled thereto and which is not a party to
         this Agreement), indemnity, warranty or guarantee payable to Agent or
         to any Pledgor from time to time with respect to any of the Pledged
         Collateral, (ii) payments (in any form whatsoever) made or due and
         payable to any Pledgor from time to time in connection with any
         requisition, confiscation, condemnation, seizure or forfeiture of all
         or any part of the Pledged Collateral by any governmental authority (or
         any person acting on behalf of a governmental authority), (iii)
         instruments representing obligations to pay amounts in respect of
         Pledged Securities or Intercompany Notes, (iv) products of the Pledged
         Collateral, and (v) other amounts from time to time paid or payable
         under or in connection with any of the Pledged Collateral.

                  Section 2. Secured Obligations. This Agreement is entered into
by each Pledgor in favor of Agent, for its benefit and the benefit of the
Lenders to secure the payment and performance in full when due, whether at
stated maturity, by acceleration or otherwise (including, without limitation,
the payment of interest and other amounts which would accrue and become due but
for the filing of a petition in bankruptcy or the operation of the automatic
stay under Section 362(a) of the Bankruptcy Code, 11 U.S.C. Section 362(a)) of:
(i) all "Obligations" of the Borrowers and/or any and every Pledgor now or
hereafter arising or incurred under or in respect of the Loan Agreement and/or
any other Loan Documents; (ii) all obligations of the Borrowers and any and
every Pledgor now or hereafter arising or incurred under or in respect of this
Agreement or any other Loan Document; and (iii) all interest, charges, fees,
costs, expenses, reimbursements, premiums, indemnities and other payments of any
kind or nature in respect of amounts or instruments referred to in any of
clauses (i) and (ii) (the obligations described in clauses (i) through (iii),
collectively, the "SECURED OBLIGATIONS").

                  Section 3. No Release. Nothing set forth in this Agreement
shall relieve any Pledgor from the performance of any term, covenant, condition
or agreement on such Pledgor's part to be performed or observed under or in
respect of any of the Pledged Collateral or from any liability to any Person
under or in respect of any of the Pledged Collateral or shall impose any
obligation on Agent or any Lender to perform or observe any such term, covenant,
condition or agreement on such Pledgor's part to be so performed or observed or
shall impose any liability on Agent or any Lender for any act or omission on the
part of any Pledgor relating thereto or for any breach of any representation or
warranty on the part of any Pledgor contained in this Agreement or any other
Loan Document or under or in respect of the Pledged Collateral or made in
connection herewith or therewith.

                  Section 4. Delivery of Pledged Collateral. (a) All
certificates, agreements, notes or instruments representing or evidencing the
Pledged Collateral, to the extent not previously delivered to Agent, shall
immediately upon receipt thereof by any Pledgor be delivered to and held by or
on behalf of Agent pursuant hereto except that stock certificates or other
evidence of Pledged Collateral relating to corporations incorporated outside of
the United States may be held by foreign counsel under an escrow arrangement
satisfactory to Agent. All Pledged

                                                            UTI-PLEDGE AGREEMENT

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Collateral shall be in suitable form for transfer by delivery or shall be
accompanied by duly executed instruments of transfer or assignment in blank, all
in form and substance reasonably satisfactory to Agent. Agent shall have the
right, at any time upon the occurrence of an Event of Default and without notice
to any Pledgor, to endorse, assign or otherwise transfer to or to register in
the name of Agent or any of its nominees any or all of the Pledged Collateral.
In addition, Agent shall have the right at any time to exchange certificates
representing or evidencing Pledged Collateral for certificates of smaller or
larger denominations.

                  (b) If the issuer of any Pledged Securities is organized in a
jurisdiction which does not permit the use of certificates to evidence equity or
partnership ownership, as the case may be, or if any of the Pledged Securities
are not evidenced by certificates of ownership or other evidence of partnership
interests, as the case may be, then the Pledgor that pledged such Pledged
Securities shall, to the extent permitted by applicable law, record such pledge
on the stock register or books of the issuer, execute any customary stock pledge
forms or other documents necessary or appropriate to complete the pledge and
give Agent the right to transfer such Pledged Securities under the terms hereof
and provide to Agent an opinion of counsel, in form and substance reasonably
satisfactory to Agent, confirming such pledge.

                  Section 5. Supplements; Further Assurances. (a) Each Pledgor
agrees that at any time and from time to time, at its sole cost and expense, it
shall promptly execute and deliver all further instruments and documents,
including, without limitation, supplemental or additional UCC-1 financing
statements, and take all further action that may be necessary or that Agent may
reasonably request, in order to perfect and protect the pledge, security
interest and Lien granted or purported to be granted hereby or to enable Agent
to exercise and enforce its rights and remedies hereunder with respect to any
Pledged Collateral.

                  (b) Each Pledgor shall, upon obtaining any Pledged Securities
or Intercompany Notes of any Person, promptly (and in any event within five
Business Days) deliver to Agent a pledge amendment, duly executed by such
Pledgor, in substantially the form of Exhibit 1 hereto (each, a "PLEDGE
AMENDMENT"), in respect of the additional Pledged Securities or Intercompany
Notes which are to be pledged pursuant to this Agreement, and confirming the
attachment of the Lien hereby created on and in respect of such additional
Pledged Securities or Intercompany Notes. Each Pledgor hereby authorizes Agent
to attach each Pledge Amendment to this Agreement and agrees that all Pledged
Securities or Intercompany Notes listed on any Pledge Amendment delivered to
Agent shall for all purposes hereunder be considered Pledged Collateral.

                  Section 6. Representations, Warranties and Covenants. Each
Pledgor, jointly and severally, represents, warrants and covenants (as
applicable), after giving effect to the transactions contemplated by the Loan
Documents as follows (as to itself and each other Pledgor):

                  (a) No Liens. Such Pledgor is, and at the time of any delivery
         of any Pledged Collateral to Agent pursuant to Section 4 of this
         Agreement will be, the sole legal and beneficial owner of the Pledged
         Collateral pledged by it. All Pledged Collateral pledged by it is on
         the date hereof, and will be, so owned by such Pledgor free and clear
         of any Lien except for the Lien created by this Agreement and the
         Security Agreement.

                                                            UTI-PLEDGE AGREEMENT

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                  (b) No Consents, etc. No consent of any party (including,
         without limitation, stockholders or creditors of such Pledgor) and no
         consent, authorization, approval, or other action by, and no notice to
         or filing with, any Governmental Authority or regulatory body or other
         Person (other than those consents or approvals which have been obtained
         as of the date hereof) is required (i) for the execution, delivery or
         performance of this Agreement by such Pledgor or for the pledge by such
         Pledgor of the Pledged Collateral pursuant to this Agreement, (ii) for
         the exercise by Agent of the voting or other rights provided for in
         this Agreement (other than any such consent, approval or action
         required to be taken by the Agent), or (iii) for the exercise by Agent
         of the remedies in respect of the Pledged Collateral pursuant to this
         Agreement (other than any such consent, approval or action required to
         be taken by the Agent).

                  (c) Due Authorization and Issuance. All of the Pledged Shares
         pledged by it have been, and to the extent hereafter issued will be
         upon such issuance, duly authorized and validly issued and fully paid
         and nonassessable to the extent permitted by applicable law. Patterson
         GP, Patterson LP and Patterson GP2 have fully paid for their respective
         Initial Pledged Partnership Interests and there is no amount or other
         obligation on the part of such Pledgors owing in exchange for their
         Initial Pledged Partnership Interest or such Pledgors' status as
         partners of PUDC, LSM, ADF, PPLP, PPTC, PUDCW and PUDCS. Parent and
         PUDC have fully paid for their respective Initial Pledged Membership
         Interests and there is no amount or obligation on the part of such
         Pledgors owing in exchange for the Initial Pledged Membership Interests
         or such Pledgors' status as members of Patterson GP, Patterson LP and
         Patterson GP2.

                  (d) Chief Executive Office. Such Pledgors' chief executive
         offices are located at addresses set forth in Schedule 7(1) of the Loan
         Agreement and each Pledgor's state of organization is Delaware. No
         Pledgor shall move its chief executive office except to such new
         location as such Pledgor may establish in accordance with the last
         sentence of this Section 6(d). No Pledgor shall establish a new
         location for its chief executive office or shall it change its name
         until (i) it shall have given Agent not less than 30 days' prior
         written notice of its intention to do so, clearly describing such new
         location or name and providing such other information in connection
         therewith as Agent or any Secured Party may reasonably request, and
         (ii) with respect to such new location or name, such Pledgor shall have
         taken all action satisfactory to Agent to maintain the perfection and
         priority of the security interest in the Pledged Collateral intended to
         be granted hereby.

                  (e) Delivery of Pledged Collateral; Filings. Such Pledgor has
         delivered (or in the case of Pledged Securities acquired by such
         Pledgor after the date hereof, such Pledgor will have delivered) to
         Agent all certificates representing the Pledged Securities and
         Intercompany Notes intended to be pledged pursuant to this Agreement
         and has directed the Agent to file UCC-1 financing statements
         (evidencing the lien created by this Agreement) with the Secretary of
         State of the State of Texas and, with respect to Holding only, the
         State of Delaware (the States in which the respective chief executive
         offices of such Pledgors are located), and such delivery and pledge of
         the Pledged Collateral pursuant to this Agreement creates, upon proper
         filing, a valid and perfected first priority security interest in the
         Pledged Collateral securing the payment of the Secured Obligations

                                                            UTI-PLEDGE AGREEMENT

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         pursuant to the Code in effect in each applicable jurisdiction,
         including, without limitation, the State of Texas and, with respect to
         Holding only, the State of Delaware.

                  (f) Pledged Collateral. All information set forth herein,
         including the Schedules annexed hereto, relating to the Pledged
         Collateral pledged by it is accurate and complete in all respects.

                  (g) No Violations, etc. The pledge of the Pledged Collateral
         pledged by it pursuant to this Agreement does not violate Regulation U
         or X of the Federal Reserve Board.

                  (h) Ownership of Pledged Collateral. Except as otherwise
         permitted by the Loan Agreement, such Pledgor at all times will be the
         sole beneficial owner of the Pledged Collateral pledged by it.

                  (i) No Options, Warrants, etc. There are no options, warrants,
         calls, rights, commitments or agreements of any character to which such
         Pledgor is a party or by which it is bound obligating such Pledgor to
         issue, deliver or sell or cause to be issued, delivered or sold,
         additional Pledged Securities or obligating such Pledgor to grant,
         extend or enter into any such option, warrant, call, right, commitment
         or agreement. There are no voting trusts or other agreements or
         understandings to which such Pledgor is a party with respect to the
         voting of the capital stock of any issuer of the Pledged Securities
         pledged by it.

                  (j) Partnership Agreements and LLC Agreements. The Pledgors
         have delivered to Agent a true, correct and complete copy of the
         Partnership Agreements and the LCC Agreements. Each of the Partnership
         Agreements and LLC Agreements is in full force and effect, has not as
         of the date hereof, been amended or modified and there is no existing
         default by any party thereunder or any event which, with the giving of
         notice or passage of time or both, would constitute a default by any
         party thereunder. No person will terminate or agree to terminate the
         Partnership Agreements or the LLC Agreements or make any amendment or
         modification to the Partnership Agreements or the LLC Agreements which
         may have a Material Adverse Effect on the value of the Pledged
         Collateral. The Pledgors shall deliver to Agent as promptly as
         practicable following the execution thereof, certified copies or
         executed originals of each such amendment and modification concurrently
         with the delivery of such documents to the parties thereto.

                  Section 7. Voting Rights; Distributions; etc. (a) So long as
no Event of Default shall have occurred and be continuing:

         (i) each Pledgor shall be entitled to exercise any and all voting and
         other consensual rights pertaining to the Pledged Securities or any
         part thereof for any purpose not inconsistent with the terms or purpose
         of this Agreement or any other Loan Document; provided, however, that
         such Pledgor shall not in any event exercise such rights in any manner
         which could reasonably be expected to have a Material Adverse Effect on
         the value of the Pledged Collateral pledged by it or an adverse effect
         on the other rights and remedies provided to the Agent by this
         Agreement.

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         (ii) Subject to the terms of the Loan Agreement, each Pledgor shall be
         entitled to receive and retain, and to utilize free and clear of the
         Lien of this Agreement, any and all Distributions, but only if and to
         the extent made in accordance with the provisions of the Loan
         Documents; provided, however, that any and all such Distributions
         consisting of rights or interests in the form of securities shall be,
         and shall be forthwith delivered to Agent to hold as Pledged Collateral
         and shall, if received by any Pledgor, be received in trust for the
         benefit of Agent, be segregated from the other property or funds of
         such Pledgor, and be forthwith delivered to Agent as Pledged Collateral
         in the same form as so received (with any necessary endorsement).

         (iii) Agent shall be deemed without further action or formality to have
         granted to each Pledgor all necessary consents relating to voting
         rights and shall, if necessary, upon written request of any Pledgor and
         at such Pledgor's sole cost and expense, from time to time execute and
         deliver (or cause to be executed and delivered) to such Pledgor all
         such instruments as such Pledgor may reasonably request in order to
         permit such Pledgor to exercise the voting and other rights which it is
         entitled to exercise pursuant to Section 7(a)(i) hereof and to receive
         the Distributions which it is authorized to receive and retain pursuant
         to Section 7(a)(ii) hereof.

                  (b) Upon the occurrence and during the continuance of an Event
of Default:

         (i) All rights of each Pledgor to exercise the voting and other
         consensual rights it would otherwise be entitled to exercise pursuant
         to Section 7(a)(i) hereof without any action or the giving of any
         notice shall cease, and all such rights shall thereupon become vested
         in Agent (for so long as such Event of Default shall be continuing),
         which shall thereupon have the sole right to exercise such voting and
         other consensual rights.

         (ii) All rights of each Pledgor to receive Distributions which it would
         otherwise be authorized to receive and retain pursuant to Section
         7(a)(ii) hereof shall cease and all such rights shall thereupon become
         vested in Agent (for so long as such Event of Default shall be
         continuing), which shall thereupon have the sole right to receive and
         hold as Pledged Collateral such Distributions.

                  (c) Each Pledgor shall, at its sole cost and expense, from
time to time execute and deliver to Agent appropriate instruments as Agent may
reasonably request in order to permit Agent to exercise the voting and other
rights which it may be entitled to exercise pursuant to Section 7(b)(i) hereof
and to receive all Distributions which it may be entitled to receive under
Section 7(b)(ii) hereof.

                  (d) All Distributions which are received by any Pledgor
contrary to the provisions of Section 7(b)(ii) hereof shall be received in trust
for the benefit of Agent, shall be segregated from other funds of such Pledgor
and shall immediately be paid over to Agent as Pledged Collateral in the same
form as so received (with any necessary endorsement).

                  Section 8. Transfers and Other Liens; Additional Shares. (a)
No Pledgor shall (i) sell, convey, assign or otherwise dispose of, or grant any
option, right or warrant with respect

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to, any of the Pledged Collateral pledged by it except as permitted by the Loan
Agreement, (ii) create or permit to exist any Lien upon or with respect to any
Pledged Collateral pledged by it other than the Lien and security interest
granted to Agent under this Agreement and the Security Agreement, or (iii)
except as permitted by the Loan Agreement, permit the issuer of any Pledged
Securities pledged by it to merge, consolidate or change its legal form, unless
all of the outstanding capital stock, partnership interests or membership
interests (as applicable) of the surviving or resulting entity is, upon such
merger or consolidation, pledged hereunder and no cash, securities or other
property is distributed in respect of the outstanding shares, partnership or
membership interests (as applicable) of any other constituent entity.

                  (b) Each Pledgor shall (i) cause each issuer of the Pledged
Securities pledged by it not to issue any stock or other securities or equity,
partnership or membership interests in addition to or in substitution for the
Pledged Securities issued by such issuer, except to such Pledgor or other
Pledgors, (ii) pledge hereunder, immediately upon its acquisition (directly or
indirectly) thereof, any and all additional shares of capital stock or other
equity, partnership or membership securities of the issuer of the Pledged
Securities which are required to be pledged hereunder and (iii) deliver all
related stock or transfer powers requested by the Agent.

                  Section 9. Reasonable Care. Agent shall be deemed to have
exercised reasonable care in the custody and preservation of the Pledged
Collateral in its possession if such Pledged Collateral is accorded treatment
substantially equivalent to that which Agent, in its individual capacity,
accords its own property consisting of similar instruments or interests, it
being understood that neither Agent nor any of the Secured Parties shall have
responsibility for (i) ascertaining or taking action with respect to calls,
conversions, exchanges, maturities, tenders or other matters relating to any
Pledged Collateral, whether or not Agent or any other Secured Party has or is
deemed to have knowledge of such matters, or (ii) taking any necessary steps to
preserve rights against any Person with respect to any Pledged Collateral.

                  Section 10. Remedies Upon Default; Decisions Relating to
Exercise of Remedies. (a) If any Event of Default shall have occurred and be
continuing, Agent shall have the right, in addition to other rights and remedies
provided for herein or otherwise available to it to be exercised from time to
time, (i) to retain and apply the Distributions to the Secured Obligations as
provided in Section 11 hereof, (ii) to exercise any remedies set forth in any
Intercompany Notes (to the extent that a default has occurred thereunder) and
(iii) to exercise all the rights and remedies of a secured party under the Code
at the time of an event of default, and Agent may also in its sole discretion,
without notice except as specified below, sell the Pledged Collateral or any
part thereof (including, without limitation, any partial interest in the Pledged
Securities) in one or more parcels at public or private sale, at any exchange,
broker's board or at any of Agent's offices or elsewhere, for cash, on credit or
for future delivery, and at such price or prices and upon such other terms as
Agent may deem commercially reasonable, irrespective of the impact of any such
sales on the market price of the Pledged Collateral. Agent or any Lender or any
of their respective Affiliates may be the purchaser of any or all of the Pledged
Collateral at any such sale and shall be entitled, for the purpose of bidding
and making settlement or payment of the purchase price for all or any portion of
the Pledged Collateral sold at such sale, to use and apply any of the Secured
Obligations owed to such Person as a credit on account of the purchase price of
any Pledged Collateral payable by such Person at such sale. Each purchaser at
any such sale shall

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acquire the property sold absolutely free from any claim or right on the part of
any Pledgor, and each Pledgor hereby waives, to the fullest extent permitted by
law, all rights of redemption, stay and/or appraisal which it now has or may at
any time in the future have under any rule of law or statute now existing or
hereafter enacted. Each Pledgor acknowledges and agrees that, to the extent
notice of sale shall be required by law, ten Business Days notice to such
Pledgor of the time and place of any public sale or the time after which any
private sale or other intended disposition is to take place shall constitute
reasonable notification of such matters. No notification need be given to a
Pledgor if it has signed, after the occurrence of an Event of Default, a
statement renouncing or modifying any right to notification of sale or other
intended disposition. Agent shall not be obligated to make any sale of Pledged
Collateral regardless of notice of sale having been given. Agent may adjourn any
public or private sale from time to time by announcement at the time and place
fixed therefor, and such sale may, without further notice, be made at the time
and place to which it was so adjourned. Each Pledgor hereby waives, to the
fullest extent permitted by law, any claims against Agent arising by reason of
the fact that the price at which any Pledged Collateral may have been sold at
such a private sale was less than the price which might have been obtained at a
public sale, even if Agent accepts the first offer received and does not offer
such Pledged Collateral to more than one offeree.

                  (b) Each Pledgor recognizes that, by reason of certain
prohibitions contained in the Securities Act of 1933, as amended (the
"SECURITIES ACT"), and applicable state securities laws, Agent may be compelled,
with respect to any sale of all or any part of the Pledged Collateral, to limit
purchasers to Persons who will agree, among other things, to acquire the Pledged
Collateral for their own account, for investment and not with a view to the
distribution or resale thereof. Each Pledgor acknowledges that any such private
sales may be at prices and on terms less favorable to Agent than those
obtainable through a public sale without such restrictions (including, without
limitation, a public offering made pursuant to a registration statement under
the Securities Act), and, notwithstanding such circumstances, agrees that any
such private sale shall be deemed to have been made in a commercially reasonable
manner and that Agent shall have no obligation to engage in public sales and no
obligation to delay the sale of any Pledged Collateral for the period of time
necessary to permit the issuer thereof to register it for a form of public sale
requiring registration under the Securities Act or under applicable state
securities laws, even if such issuer would agree to do so.

                  (c) If Agent determines to exercise its right hereunder to
sell any or all of the Pledged Collateral, upon written request, each Pledgor
shall from time to time furnish to Agent all such information as Agent may
request in order to determine the number of securities included in the Pledged
Collateral which may be sold by Agent as exempt transactions under the
Securities Act and the rules of the Securities and Exchange Commission
thereunder, as the same are from time to time in effect.

                  (d) In addition to any of the other rights and remedies
hereunder, Agent shall have the right to institute a proceeding seeking specific
performance in connection with any of the agreements or obligations hereunder.

                  (e) Notwithstanding any other provision of this Agreement to
the contrary, if, after giving effect to (i) any sale, transfer or other
disposition of any or all of the Pledged

                                                            UTI-PLEDGE AGREEMENT

                                       10
<PAGE>   11


Collateral pursuant hereto and after the application of the proceeds hereunder
to the Secured Obligations and (ii) the sale, transfer or other disposition of
any collateral pledged pursuant to any other Loan Document and the application
of such proceeds thereunder, any Secured Obligation remains unpaid or
unsatisfied, each Pledgor shall remain liable for the unpaid and unsatisfied
amount of such Secured Obligations for which such Pledgor is otherwise liable
pursuant to the Loan Agreement or otherwise.

                  Section 11. Application of Proceeds. All Distributions held
from time to time by Agent in accordance with the terms of this Agreement and
all proceeds received by Agent in respect of any sale of, collection from, or
other realization upon all or any part of the Pledged Collateral pursuant to the
exercise by Agent of its remedies as a secured creditor as provided in Section
10 hereof shall be applied, together with any other sums then held by Agent
pursuant to this Agreement, promptly by Agent as follows:

                  FIRST, to the payment of all costs and expenses, fees,
         commissions and taxes of such sale, collection or other realization,
         including, without limitation, compensation to Agent and its agents and
         the reasonable fees and expenses of its counsel, and all expenses,
         liabilities and advances made or incurred by Agent in connection
         therewith, together with interest on each such amount at the highest
         rate then in effect under the Loan Agreement from and after the date
         such amount is due, owing or unpaid until paid in full;

                  SECOND, to the payment of all other costs and expenses of such
         sale, collection or other realization, including, without limitation,
         compensation to the Lenders and their agents and the reasonable fees
         and expenses of their counsel and all costs, liabilities and
         indebtedness made or incurred by the Lenders in connection therewith,
         together with interest on each such amount at the highest rate then in
         effect under the Loan Agreement from and after the date such amount is
         due, owing or unpaid until paid in full;

                  THIRD, to the indefeasible payment in full in cash of interest
         and all amounts other than principal under the Loan Agreement at any
         time and from time to time owing by any Pledgor under or in connection
         with the Loan Agreement, ratably according to the unpaid amounts
         thereof, without preference or priority of any kind among amounts so
         due and payable, together with interest on each such amount at the
         highest rate then in effect under the Loan Agreement from and after the
         date such amount is due, owing or unpaid until paid in full;

                  FOURTH, to the indefeasible payment in full in cash of
         principal at any time and from time to time owing by the Pledgors under
         or in connection with the Loan Agreement, ratably according to the
         unpaid amounts thereof, without preference or priority of any kind,
         among amounts so due and payable, together with interest on each such
         amount at the highest rate then in effect under the Loan Agreement from
         and after the date such amount is due, owing or unpaid until paid in
         full; and

                  FIFTH, the balance, if any, to the Person lawfully entitled
         thereto (including Pledgor or its successors or assigns).

                                                            UTI-PLEDGE AGREEMENT

                                       11
<PAGE>   12


                  Section 12. Expenses. Each Pledgor with respect to itself and
jointly and severally with respect to all other Pledgors, will upon demand pay
to Agent the amount of any and all expenses of Agent in connection with this
Agreement in accordance with Sections 7, Paragraph 13, Section 8, Paragraph 5
and Section 10, Paragraph 3 of the Loan Agreement. All amounts payable by any
Pledgor under this Section 12 shall be due upon demand and shall be part of the
Secured Obligations. Each Pledgor's obligations under this Section shall survive
the termination of this Agreement and the discharge of such Pledgor's other
obligations hereunder.

                  Section 13. No Waiver; Cumulative Remedies. (a) No failure on
the part of Agent to exercise, no course of dealing with respect to, and no
delay on the part of Agent in exercising, any right, power or remedy hereunder
shall operate as a waiver thereof; nor shall any single or partial exercise of
any such right, power or remedy hereunder preclude any other or further exercise
thereof or the exercise of any other right, power or remedy. The remedies herein
provided are cumulative and are not exclusive of any remedies provided by law.

                  (b) In the event Agent shall have instituted any proceeding to
enforce any right, power or remedy under this Agreement by foreclosure, sale,
entry or otherwise, and such proceeding shall have been discontinued or
abandoned for any reason or shall have been determined adversely to Agent, then
and in every such case, each Pledgor, Agent and each holder of any of the
Secured Obligations shall, subject to any determination in such proceeding, be
restored to their respective former positions and rights hereunder with respect
to the Pledged Collateral, and all rights, remedies and powers of Agent and the
Secured Parties shall continue as if no such proceeding had been instituted.

                  Section 14. Agent. CITBC has been appointed as agent for
itself as a Lender and for the other Lenders pursuant to Section 13, Paragraph 1
of the Loan Agreement. CITBC, as a Lender for itself and the other Lenders
(under the Loan Agreement), hereby confirms and restates such appointment as if
set forth at length herein. The actions of Agent hereunder are subject to the
provisions of the Loan Agreement. Agent shall have the right hereunder to make
demands, to give notices, to exercise or refrain from exercising any rights, and
to take or refrain from taking action (including, without limitation, the
release or substitution of Pledged Collateral), in accordance with this
Agreement and the Loan Agreement. Agent may resign and a successor Agent may be
appointed in the manner provided in the Loan Agreement. Upon the acceptance of
any appointment as Agent by a successor Agent, that successor Agent shall
thereupon succeed to and become vested with all the rights, powers, privileges
and duties of the retiring Agent under this Agreement, and the retiring Agent
shall thereupon be discharged from its duties and obligations under this
Agreement. After any retiring Agent's resignation, the provisions of this
Agreement shall inure to its benefit as to any actions taken or omitted to be
taken by it under this Agreement while it was Agent.

                  Section 15. Agent May Perform; Agent Appointed
Attorney-in-Fact. If any Pledgor shall fail to do any act or thing that it has
covenanted to do hereunder or any warranty on the part of any Pledgor contained
herein shall be breached, Agent may (but shall not be obligated to), upon notice
to any such Pledgor, do the same or cause it to be done or remedy any such
breach, and may expend funds for such purpose. Any and all amounts so expended
by Agent shall be paid by such Pledgor promptly upon demand therefor, with
interest at the highest rate then in

                                                            UTI-PLEDGE AGREEMENT

                                       12
<PAGE>   13


effect under the Loan Agreement during the period from and including the date on
which such funds were so expended to the date of repayment. Each Pledgor's
obligations under this Section 15 shall survive the termination of this
Agreement and the discharge of such Pledgor's other obligations under the Loan
Agreement and the other Loan Documents. Each Pledgor hereby appoints Agent its
attorney-in-fact, with full authority in the place and stead of such Pledgor and
in the name of such Pledgor, or otherwise, from time to time during the
continuance of an Event of Default or at any other time that such Pledgor has
failed, after notice from Agent, to take any action required to be taken by it
hereunder, in Agent's discretion to take any action and to execute any
instrument consistent with the terms of this Agreement and the Loan Agreement
which Agent may deem necessary or advisable to accomplish the purposes of this
Agreement. The foregoing grant of authority is a power of attorney coupled with
an interest and such appointment shall be irrevocable for the term of this
Agreement. Each Pledgor hereby ratifies, to the fullest extent permitted by law,
all that such attorney shall lawfully do or cause to be done by virtue hereof.

                  Section 16. Indemnity.

                  (a) INDEMNITY. EACH OF PLEDGORS WITH RESPECT TO ITSELF, AND
JOINTLY AND SEVERALLY WITH RESPECT TO THE OTHER PLEDGORS, AGREES TO INDEMNIFY,
PAY AND HOLD HARMLESS AGENT AND EACH OF THE LENDERS IN ACCORDANCE WITH THE
PROVISIONS OF SECTION 7, PARAGRAPH 13 OF THE LOAN AGREEMENT. TO THE EXTENT THAT
THE UNDERTAKING TO INDEMNIFY, PAY AND HOLD HARMLESS SET FORTH IN THE PRECEDING
SENTENCE MAY BE UNENFORCEABLE BECAUSE IT IS VIOLATIVE OF ANY LAW OR PUBLIC
POLICY, EACH PLEDGOR SHALL CONTRIBUTE THE MAXIMUM PORTION WHICH IT IS PERMITTED
TO PAY AND SATISFY UNDER APPLICABLE LAW, TO THE PAYMENT AND SATISFACTION OF ALL
INDEMNIFIED LIABILITIES INCURRED BY THE INDEMNITEES OR ANY OF THEM.

                  (b) Survival. The obligations of each Pledgor contained in
this Section 16 shall survive the termination of this Agreement and the
discharge of such Pledgor's other obligations under this Agreement and the other
Loan Documents.

                  (c) Reimbursement. Any amounts paid by any indemnitee as to
which such indemnitee has the right to reimbursement shall constitute Secured
Obligations secured by the Pledged Collateral.

                  Section 17. Modification in Writing. No amendment,
modification, supplement, termination or waiver of or to any provision of this
Agreement, nor consent to any departure by any Pledgor therefrom, shall be
effective unless the same shall be done in accordance with the terms of this
Agreement and the Loan Agreement. Any amendment, modification or supplement of
or to any provision of this Agreement, any waiver of any provision of this
Agreement and any consent to any departure by any Pledgor from the terms of any
provision of this Agreement, shall be effective only in the specific instance
and for the specific purpose for which made or given. Except where notice is
specifically required by this Agreement, no notice to or demand on any

                                                            UTI-PLEDGE AGREEMENT

                                       13

<PAGE>   14


Pledgor in any case shall entitle such Pledgor to any other or further notice or
demand in similar or other circumstances.

                  Section 18. Termination; Release. When all the Secured
Obligations have been indefeasibly paid in full in cash and all of the Revolving
Loan Commitments of the Lenders to make any Loan or to issue (or cause a bank to
issue) any Letter of Credit under the Loan Agreement have expired, this
Agreement shall terminate. Upon termination of this Agreement or any release of
Pledged Collateral in accordance with the provisions of the Loan Agreement, the
Agent shall, upon the request and at the sole cost and expense of any Pledgor,
forthwith assign, transfer and deliver to such Pledgor, against receipt and
without recourse to or warranty by Agent, such of the Pledged Collateral pledged
by it to be released (in the case of a release) as may be in the possession of
Agent and as shall not have been sold or otherwise applied pursuant to the terms
hereof, and, with respect to any other Pledged Collateral, proper instruments
(including, without limitation, Uniform Commercial Code termination statements
on Form UCC-3) acknowledging the termination of this Agreement or the release of
such Pledged Collateral, as the case may be.

                  Section 19. Notices. All notices or other communications
herein required to be given shall be given at the address and in the manner
required in the Loan Agreement.

                  Section 20. Continuing Security Interest; Assignment. This
Agreement shall create a continuing security interest in the Pledged Collateral
and shall (a) be binding upon each Pledgor, and its successors and assigns and
(b) inure, together with the rights and remedies of Agent hereunder, to the
benefit of Agent and the other Secured Parties and each of their respective
successors, transferees and assigns; no other Persons (including, without
limitation, any other creditor of any Pledgor) shall have any interest herein or
any right or benefit with respect hereto.

                  Section 21. GOVERNING LAW; TERMS. THIS AGREEMENT SHALL BE
GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF NEW YORK, EXCEPT TO THE EXTENT THAT THE VALIDITY OR PERFECTION OF
THE SECURITY INTEREST HEREUNDER, OR REMEDIES HEREUNDER, IN RESPECT OF ANY
PARTICULAR PROPERTY ARE GOVERNED BY THE LAWS OF A JURISDICTION OTHER THAN THE
STATE OF NEW YORK (INCLUDING, BUT NOT LIMITED TO, SECTION 5-1401 OF THE GENERAL
OBLIGATIONS LAW OF THE STATE OF NEW YORK).

                  Section 22. CONSENT TO JURISDICTION AND SERVICE OF PROCESS.
ALL JUDICIAL PROCEEDINGS BROUGHT AGAINST ANY PLEDGOR WITH RESPECT TO THIS
AGREEMENT MAY BE BROUGHT IN ANY STATE OR FEDERAL COURT OF COMPETENT JURISDICTION
IN THE STATE OF NEW YORK AND BY EXECUTION AND DELIVERY OF THIS AGREEMENT EACH
PLEDGOR ACCEPTS FOR ITSELF AND IN CONNECTION WITH ITS PROPERTIES, GENERALLY AND
UNCONDITIONALLY, THE NONEXCLUSIVE JURISDICTION OF THE AFORESAID COURTS, AND
IRREVOCABLY AGREES TO BE BOUND BY ANY JUDGMENT RENDERED THEREBY IN CONNECTION
WITH THIS AGREEMENT. EACH PARTY HERETO HEREBY

                                                            UTI-PLEDGE AGREEMENT

                                       14
<PAGE>   15


IRREVOCABLY WAIVES TRIAL BY JURY, AND EACH PARTY HERETO HEREBY IRREVOCABLY
WAIVES ANY OBJECTION, INCLUDING, WITHOUT LIMITATION, ANY OBJECTION TO THE LAYING
OF VENUE OR BASED ON THE GROUNDS OF FORUM NON CONVENIENS, WHICH IT MAY NOW OR
HEREAFTER HAVE TO THE BRINGING OF ANY SUCH ACTION OR PROCEEDING IN SUCH
RESPECTIVE JURISDICTIONS.

                  Section 23. Severability of Provisions. Any provision of this
Agreement which is prohibited or unenforceable in any jurisdiction shall, as to
such jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions hereof or
affecting the validity or enforceability of such provision in any other
jurisdiction.

                  Section 24. Execution in Counterparts. This Agreement and any
amendments, waivers, consents or supplements hereto may be executed in any
number of counterparts and by different parties hereto in separate counterparts,
each of which when so executed and delivered shall be deemed to be an original,
but all such counterparts together shall constitute one and the same agreement.

                  Section 25. Headings. The Section headings used in this
Agreement are for convenience of reference only and shall not affect the
construction of this Agreement.

                  Section 26. Obligations Absolute. All obligations of each
Pledgor hereunder shall be absolute and unconditional irrespective of:

         (i) any bankruptcy, insolvency, reorganization, arrangement,
         readjustment, composition, liquidation or the like of any other
         Pledgor;

         (ii) any lack of validity or enforceability of the Loan Agreement, any
         other Loan Document, or any other agreement or instrument relating
         thereto;

         (iii) any change in the time, manner or place of payment of, or in any
         other term of, all or any of the Secured Obligations, or any other
         amendment or waiver of or any consent to any departure from the Loan
         Agreement, any other Loan Document, or any other agreement or
         instrument relating thereto;

         (iv) any exchange, release or non-perfection of any collateral or the
         pledge of any additional collateral or the failure to recover in
         respect thereof pursuant to any remedy or right of the Agent or any
         Lender contained in this Agreement, the Loan Agreement, or any release
         or amendment or waiver of or consent to any departure from any
         guarantee, for all or any of the Secured Obligations;

         (v) any exercise or non-exercise, or any waiver of any right, remedy,
         power or privilege under or in respect of this Agreement or any Loan
         Document except as specifically set forth in a waiver granted pursuant
         to the provisions of Section 17 hereof; or

                                                            UTI-PLEDGE AGREEMENT

                                       15
<PAGE>   16



         (vi) any other circumstances which might otherwise constitute a defense
         available to, or a discharge of, any Pledgor.

                  Section 27. Agent's Right to Sever Indebtedness. (a) Each
Pledgor acknowledges that (i) the Pledged Collateral does not constitute the
sole source of security for the payment and performance of the Secured
Obligations and that the Secured Obligations are also secured by other types of
property of such Pledgor and its Affiliates in other jurisdictions (all such
property, collectively, the "COLLATERAL"), (ii) the number of such jurisdictions
and the nature of the transaction of which this instrument is a part are such
that it would have been impracticable for the parties to allocate to each item
of Collateral a specific loan amount and to execute in respect of such item a
separate credit agreement and security agreement, and (iii) each Pledgor intends
that Agent have the same rights with respect to the Pledged Collateral, in any
judicial proceeding relating to the exercise of any right or remedy hereunder or
otherwise, that Agent would have had if each item of Collateral had been pledged
or encumbered pursuant to a separate credit agreement and security agreement. In
furtherance of such intent, each Pledgor agrees to the greatest extent permitted
by law that, from and after the occurrence of an Event of Default, Agent may at
its option, at any time and from time to time, by notice (an "ALLOCATION
NOTICE") to such Pledgor allocate a portion of the Secured Obligations (the
"ALLOCATED INDEBTEDNESS") to the Pledged Collateral pledged by it and sever from
the remaining Secured Obligations the Allocated Indebtedness. From and after the
giving of an Allocation Notice with respect to the Pledged Collateral, the
Secured Obligations hereunder shall be limited to the extent set forth in the
Allocation Notice and (as so limited) shall, for all purposes, be construed as a
separate credit obligation of such Pledgor unrelated to the other transactions
contemplated by the Loan Agreement. To the extent that the proceeds of any
judicial proceeding relating to the exercise of any right or remedy hereunder of
the Pledged Collateral shall exceed the Allocated Indebtedness, such proceeds
shall belong to such Pledgor and shall not be available hereunder to satisfy any
Secured Obligations of such Pledgor other than the Allocated Indebtedness. In
any action or proceeding to exercise any right or remedy under this Agreement
which is commenced after the giving by Agent of an Allocation Notice, the
Allocation Notice shall be conclusive proof of the limits of the Secured
Obligations hereby secured, and such Pledgor may introduce, by way of defense or
counterclaim, evidence thereof in any such action or proceeding. Notwithstanding
any provision of this Section 27, the proceeds received by the Agent pursuant to
this Agreement shall be applied by the Agent in accordance with the provisions
of Section 11 hereof.

                  (b) Each Pledgor hereby waives to the fullest extent permitted
by law the right to a discharge of any of the Secured Obligations under any
statute or rule of law now or hereafter in effect which provides that the
exercise of any particular right or remedy as provided for herein (by judicial
proceedings or otherwise) constitutes the exclusive means for satisfaction of
the Secured Obligations or which makes unavailable any further judgment or any
other right or remedy provided for herein because the Agent elected to proceed
with the exercise of such initial right or remedy or because of any failure by
Agent to comply with laws that prescribe conditions to the entitlement to such
subsequent judgment or the availability of such subsequent right or remedy. In
the event that, notwithstanding the foregoing waiver, any court shall for any
reason hold that such subsequent judgment or action is not available to Agent,
no Pledgor shall to the extent permitted by applicable law, (i) introduce in any
other jurisdiction any judgment so holding as a defense to enforcement against
such Pledgor of any remedy in the Loan Agreement or any

                                                            UTI-PLEDGE AGREEMENT

                                       16
<PAGE>   17


other Loan Document or (ii) seek to have such judgment recognized or entered in
any other jurisdiction, and any such judgment shall in all events be limited in
application only to the state or jurisdiction where rendered and only with
respect to the Collateral referred to in such judgment.

                  (c) In the event any instrument in addition to the Allocation
Notice is necessary to effectuate the provisions of this Section 27, including,
without limitation, any amendment to this Agreement, any substitute promissory
note or affidavit or certificate of any kind, each Pledgor agrees that it shall
execute and deliver any such instrument reasonably requested by the Agent so
long as such instrument is consistent with the terms of the Loan Documents.

                                                            UTI-PLEDGE AGREEMENT

                                       17
<PAGE>   18


         IN WITNESS WHEREOF, each Pledgor and the Agent have caused this
Agreement to be duly executed and delivered by their duly authorized officers as
of the date first above written.

PLEDGORS:

PATTERSON-UTI ENERGY, INC.

By:
   ------------------------------------------------
Name:
     ----------------------------------------------
Title:
      ---------------------------------------------


PATTERSON (LP) LLC

By:
   ------------------------------------------------
Name:
     ----------------------------------------------
Title:
      ---------------------------------------------


PATTERSON (GP) LLC

By:
   ------------------------------------------------
Name:
     ----------------------------------------------
Title:
      ---------------------------------------------


PATTERSON (GP2) LLC

By:
   ------------------------------------------------
Name:
     ----------------------------------------------
Title:
      ---------------------------------------------


 PATTERSON-UTI DRILLING COMPANY LP, LLLP

 By:     Patterson (GP) LLC, its general partner

         By:
              ------------------------------------------
         Name:
                ----------------------------------------
         Title:
                 ---------------------------------------

AGENT:

THE CIT GROUP/BUSINESS CREDIT, INC.

By:
     ------------------------------------------
Name:
       ----------------------------------------
Title:
        ---------------------------------------

                                                            UTI-PLEDGE AGREEMENT

<PAGE>   19


         The undersigned hereby each agrees that it will comply with
instructions originated by Pledgee without further consent by Pledgor. It is
intended that this undertaking by the undersigned confer control over the
Pledged Interests on Pledgee for purposes of perfecting Pledgee's security
interest in the Pledged Interests under the Code.

<Table>
<Caption>

PATTERSON (LP) LLC                                                   PATTERSON-UTI DRILLING COMPANY LP, LLLP

<S>                                                                  <C>
By:                                                                  By:  Patterson (GP) LLC, its general partner
   ----------------------------------------
Name:
     --------------------------------------
Title:                                                                         By:
      -------------------------------------                                       ----------------------------------
                                                                               Name:
                                                                                    --------------------------------
PATTERSON (GP) LLC                                                             Title:
                                                                                     -------------------------------
By:
   ----------------------------------------                           PATTERSON-UTI DRILLING COMPANY SOUTH LP, LLLP
Name:
     --------------------------------------                           By:  Patterson (GP2) LLC., its general partner
Title:
      -------------------------------------                                    By:
                                                                                  ----------------------------------
                                                                               Name:
PATTERSON (GP2) LLC                                                                 --------------------------------
                                                                               Title:
By:                                                                                   ------------------------------
   ----------------------------------------
Name:                                                                 PATTERSON-UTI DRILLING COMPANY WEST LP, LLLP
     --------------------------------------
Title:                                                                By:  Patterson (GP2) LLC, its general partner
      -------------------------------------

                                                                                By:
PATTERSON PETROLEUM LP, LLLP                                                       ---------------------------------
                                                                                Name:
By:  Patterson (GP) LLC, its general partner                                         -------------------------------
                                                                                Title:
          By:                                                                          -----------------------------
             ------------------------------
          Name:                                                        LONE STAR MUD LP, LLLP
               ----------------------------
          Title:                                                       By:  Patterson (GP) LLC, its general partner
                ---------------------------

                                                                                By:
PATTERSON PETROLEUM TRADING COMPANY LP,                                            ---------------------------------
LLLP                                                                            Name:
                                                                                     -------------------------------
 By: Patterson (GP) LLC, its general partner                                    Title:
                                                                                      ------------------------------
          By:
             ------------------------------
          Name:                                                        AMBAR DRILLING FLUIDS LP, LLLP
               ----------------------------
          Title:                                                       By:  Patterson (GP) LLC, its general partner
                ---------------------------

                                                                               By:
                                                                                  ---------------------------------
                                                                               Name:
                                                                                    -------------------------------
                                                                               Title:
                                                                                     ------------------------------

</TABLE>

                                                            UTI-PLEDGE AGREEMENT

<PAGE>   20



                                   SCHEDULE A

                               PLEDGED SECURITIES


UTICO, INC.:
         (1)  1,000 shares of common stock owned by Patterson-UTI Energy, Inc.


PATTERSON (GP) LLC:
         (1)  100% membership interest owned by Patterson-UTI Energy, Inc.


PATTERSON (LP) LLC:
         (1)  100% membership interest owned by Patterson-UTI Energy, Inc.


AMBAR DRILLING FLUIDS LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP) LLC
         (2)  99%. Limited Partnership interest owned by Patterson (LP) LLC

LONE STAR MUD LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP) LLC
         (2)  99% Limited Partnership interest owned by Patterson (LP) LLC

PATTERSON - UTI DRILLING COMPANY LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP) LLC
         (2)  99%. Limited Partnership interest owned by Patterson (LP) LLC

PATTERSON PETROLEUM LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP) LLC
         (2)  99%. Limited Partnership interest owned by Patterson (LP) LLC

PATTERSON PETROLEUM TRADING COMPANY, LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP) LLC
         (2)  99%. Limited Partnership interest owned by Patterson (LP) LLC

PATTERSON (GP2) LLC
         (1)  100% membership interest owned by Patterson UTI Drilling Company
              LP, LLLP

PATTERSON - UTI DRILLING COMPANY SOUTH LP, LLLP

         (1)  1% General Partnership interest owned by Patterson (GP2) LLC
         (2)  99% Limited Partnership interest owned by Patterson - UTI Drilling
              Company LP, LLLP

PATTERSON UTI DRILLING COMPANY WEST LP, LLLP
         (1)  1% General Partnership interest owned by Patterson (GP2) LLC
         (2)  99% Limited Partnership interest owned by Patterson - UTI Drilling
              Company LP, LLLP

                                                            UTI-PLEDGE AGREEMENT

<PAGE>   21


                                   SCHEDULE B

                               INTERCOMPANY NOTES


                                     [None]

                                                            UTI-PLEDGE AGREEMENT

<PAGE>   22



                                    EXHIBIT 1

                                PLEDGE AMENDMENT


         This Pledge Amendment, dated , is delivered pursuant to Section 5 of
the Agreement referred to below. The undersigned hereby agrees that this Pledge
Amendment may be attached to the Pledge Agreement, dated as of June 29, 2001,
between the undersigned, certain other parties identified therein and THE CIT
GROUP/BUSINESS CREDIT, INC., as Agent (the "AGREEMENT"; capitalized terms used
herein and not defined have the meanings ascribed to them in the Agreement) and
that the Pledged Securities and/or Intercompany Notes listed on this Pledge
Amendment shall be deemed to be and shall become part of the Pledged Collateral
and shall secure all Secured Obligations.


                                        ---------------------------------------
                                        Pledgor




                                        By:
                                           ------------------------------------
                                           Name:
                                                -------------------------------
                                           Title:
                                                 ------------------------------

                                                            UTI-PLEDGE AGREEMENT