<PAGE>

                                                                    EXHIBIT 4.10

                             AMENDMENT NO. 5 TO THE
                                CREDIT AGREEMENT

                                                      Dated as of June 30, 2003

   AMENDMENT NO. 5 TO THE CREDIT AGREEMENT among DRESSER, INC., a Delaware
corporation (the "U.S. Borrower"), and D.I. LUXEMBOURG S.A.R.L., a corporation
organized and existing under the laws of Luxembourg (the "Euro Borrower", and,
collectively with the U.S. Borrower, the "Borrowers"), DEG ACQUISITIONS, LLC, a
limited liability company organized and existing under the laws of Delaware
("DEG Acquisitions"), DRESSER HOLDINGS, INC., a Delaware corporation ("Dresser
Holdings"), the Subsidiary Guarantors party to the Credit Agreement referred to
below (the "Subsidiary Guarantors"), the banks, financial institutions and other
institutional lenders party to the Credit Agreement referred to below
(collectively, the "Lenders"), WELLS FARGO BANK TEXAS, N.A., as the swing line
bank, MORGAN STANLEY & CO. INCORPORATED, as collateral agent (the "Collateral
Agent"), MORGAN STANLEY SENIOR FUNDING, INC., as administrative agent (the
"Administrative Agent") for the Lenders and CREDIT SUISSE FIRST BOSTON, as
syndication agent (the "Syndication Agent", and together with the Collateral
Agent and the Administrative Agent, the "Agents").

   PRELIMINARY STATEMENTS:

   (1) The Borrowers, DEG Acquisitions, the Subsidiary Guarantors, the Lenders
and the Agents have entered into a Credit Agreement dated as of April 10, 2001,
as amended by Amendment No. 1 thereto dated as of March 13, 2002, Amendment No.
2 thereto dated as of June 17, 2002, Amendment No. 3 thereto dated as of
December 11, 2002 and Amendment No. 4 and Waiver thereto dated as of March 31,
2003 (such Credit Agreement, as amended, supplemented or otherwise modified
through the date hereof, the "Credit Agreement"). Dresser Holdings has entered
into an Assignment and Assumption Agreement dated as of July 3, 2002 with DEG
Acquisitions whereby Dresser Holdings assumed the duties and liabilities of DEG
Acquisitions under the Credit Agreement and the Security Agreement. Capitalized
terms not otherwise defined in this Amendment No. 5 have the same meanings as
specified in the Credit Agreement.

   (2) The Borrowers have requested that the Lenders amend certain provisions of
the Credit Agreement as provided herein.

   (3) The Lenders party hereto, constituting not less than the Required Lenders
are, on the terms and conditions stated below, willing to grant the request of
the Borrowers as hereinafter set forth.

   NOW, THEREFORE, for good and valuable consideration the sufficiency of which
is hereby acknowledged, and subject to the terms and conditions of this
Amendment No. 5, the parties agree as follows:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

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                                        2

   SECTION 1. The Amendment. Subject to the satisfaction of the conditions
precedent set forth in Section 2, the definition of "EBITDA" in Section 1.01 of
the Credit Agreement is hereby amended and restated in its entirety as follows:

          ""EBITDA" means, in each case of the U.S. Borrower and each of its
       Subsidiaries, for any period, the sum (without duplication) of (a) Net
       Income, (b) to the extent Net Income has been reduced thereby, (i) all
       income taxes and foreign withholding taxes paid or accrued for such
       period, (ii) Interest Expense, (iii) Non-cash Charges less any non-cash
       items increasing Net Income for such period (other than normal accruals
       in the ordinary course of business), (iv) any cash charges resulting from
       the Transactions and the related financings that, in each case, are
       incurred prior to the six month anniversary of the Initial Extension of
       Credit, and (v) any non-capitalized transactions costs incurred in
       connection with actual, proposed or abandoned financings, acquisitions or
       divestitures, including, but not limited to, financing and refinancing
       fees and costs incurred in connection with the Transactions, all as
       determined in accordance with GAAP for such period, and (c) an allowance
       for losses (including lost earnings and incremental costs) incurred by
       the U.S. Borrower during the second and third fiscal quarters of the
       Fiscal Year ended December 31, 2003 attributable to a labor dispute at
       the Waukesha plant commencing on or about May 1, 2003, as reasonably
       determined in good faith by the U.S. Borrower, in an aggregate amount for
       all such losses under this clause (c) not to exceed $13,000,000, provided
       that, for purposes of the last fiscal quarter of Fiscal Year 2000 and the
       first fiscal quarter of Fiscal Year 2001, Consolidated EBITDA of the U.S.
       Borrower and its Subsidiaries shall mean, respectively U.S.$58,300,000
       and U.S.$54,900,000, provided, further that, for purposes of each of the
       second, third and fourth fiscal quarters of the Fiscal Year ended in
       2002, Consolidated EBITDA of the U.S. Borrower and its Subsidiaries shall
       mean, respectively, U.S.$47,700,000, U.S.$46,900,000 and
       U.S.$29,400,000."

   SECTION 2. Conditions of Effectiveness. This Amendment No. 5 shall become
effective as of the first date (the "Amendment No. 5 Effective Date") on which
each of the following conditions precedents shall have been satisfied:

      (a) The Administrative Agent shall have received counterparts of this
   Amendment No. 5 executed by the Borrowers, DEG Acquisitions, Dresser Holdings
   and the Required Lenders or, as to any of the Lenders, advice satisfactory to
   the Administrative Agent that such Lender has executed this Amendment No. 5.

      (b) All of the accrued fees and expenses of the Administrative Agent and
   the Lender Parties (including the accrued fees and expenses of counsel for
   the Administrative Agent) shall have been paid in full.

      (c) The Administrative Agent shall have received the consent attached
   hereto duly executed by each Guarantor and each Grantor.

                             Amendment No. 5 to the
                            Dresser Credit Agreement

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                                        3

      (d) The U.S. Borrower shall have paid to the Administrative Agent, for the
   benefit of the applicable Lenders, a fee equal to 0.05% of the aggregate
   Commitments of each Lender that has executed and delivered this Amendment No.
   5 on or before July 11, 2003.

   This Amendment No. 5 is subject to the provisions of Section 9.01 of the
Credit Agreement.

   SECTION 3. Representations and Warranties of the Borrower. Each Borrower
represents and warrants as follows:

      (a) On the date hereof, after giving effect to this Amendment No. 5, (i)
   no event has occurred and is continuing, or would result from the
   effectiveness of this Amendment No. 5, that constitutes a Default and (ii)
   all representations and warranties set forth in the Loan Documents shall be
   true and correct in all material respects.

      (b) No authorization or approval or other action by, and no notice to or
   filing with, any governmental authority or regulatory body or any other third
   party is required for the due execution, delivery or performance by the
   Borrowers of this Amendment No. 5 and by the Guarantors and the Grantors of
   the consent attached hereto or other transactions contemplated hereby.

      (c) This Amendment No. 5 has been duly executed and delivered by the
   Borrowers. The consent attached hereto has been duly executed and delivered
   by each of the Guarantors and the Grantors. This Amendment No. 5 and each of
   the other Loan Documents, as amended hereby, to which each Borrower, each
   Guarantor and each Grantor is a party are legal, valid and binding
   obligations of such Borrower, such Guarantor and such Grantor, as applicable,
   enforceable against such Borrower, such Guarantor and such Grantor, as
   applicable, in accordance with their respective terms.

   SECTION 4. Reference to and Effect on the Credit Agreement and the Notes. (a)
On and after the effectiveness of this Amendment No. 5, each reference in the
Credit Agreement to "this Agreement", "hereunder", "hereof" or words of like
import referring to the Credit Agreement, and each reference in the Notes and
each of the other Loan Documents to "the Credit Agreement", "thereunder",
"thereof" or words of like import referring to the Credit Agreement, shall mean
and be a reference to the Credit Agreement, as amended by this Amendment No. 5.

   (b) The Credit Agreement, the Notes and each of the other Loan Documents, as
specifically amended by this Amendment No. 5, are and shall continue to be in
full force and effect and are hereby in all respects ratified and confirmed.
Without limiting the generality of the foregoing, the Collateral Documents and
all of the Collateral described therein do and shall continue to secure the
payment of all Obligations of the Loan Parties under the Loan Documents, in each
case as amended by this Amendment No. 5.

   (c) The execution, delivery and effectiveness of this Amendment No. 5 shall
not, except as expressly provided herein, operate as a waiver of any right,
power or remedy of

                             Amendment No. 5 to the
                            Dresser Credit Agreement

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                                        4

any Lender or the Administrative Agent under any of the Loan Documents, nor
constitute a waiver of any provision of any of the Loan Documents.

   SECTION 5. Execution in Counterparts. This Amendment No. 5 may be executed in
any number of counterparts and by different parties hereto in separate
counterparts, each of which when so executed shall be deemed to be an original
and all of which taken together shall constitute but one and the same agreement.
Delivery of an executed counterpart of a signature page to this Amendment No. 5
by telecopier shall be effective as delivery of a manually executed counterpart
of this Amendment No. 5.

   SECTION 6. Governing Law. This Amendment No. 5 shall be governed by, and
construed in accordance with, the laws of the State of New York.

                      [SIGNATURE PAGES IMMEDIATELY FOLLOW]

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>

   IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 5 to be
executed by their respective officers thereunto duly authorized, as of the date
first above written.

                                             DRESSER, INC., as U.S. Borrower

                                             By ____________________________
                                                Name:
                                                Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>

                                             D.I. LUXEMBOURG S.A.R.L., as Euro
                                             Borrower

                                             By ____________________________
                                                Name:
                                                Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

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                                      DEG ACQUISITIONS, LLC

                                      By: FIRST RESERVE FUND VIII, L.P.,
                                          a Delaware limited partnership, its
                                            Manager
                                          By: FIRST RESERVE GP VIII, L.P.,
                                              a Delaware limited partnership,
                                              its general partner

                                              By: FIRST RESERVE CORPORATION,
                                                  a Delaware corporation, its
                                                  general partner

                                              By: ___________________________
                                                  Name:
                                                  Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>

                                             DRESSER HOLDINGS, INC.

                                             By ____________________________
                                                Name:
                                                Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>


                                             MORGAN STANLEY SENIOR FUNDING,
                                             INC., as Administrative Agent

                                             By ____________________________
                                                Name:
                                                Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>

                                             MORGAN STANLEY & CO. INCORPORATED,
                                             as Collateral Agent

                                             By ____________________________
                                                Name:
                                                Title:

                             Amendment No. 5 to the
                            Dresser Credit Agreement

<PAGE>

                                          CREDIT SUISSE FIRST BOSTON
                                          as Syndication Agent

                                          By. __________________________________
                                              Name:
                                              Title:


                                          By. __________________________________
                                              Name:
                                              Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                          GENERAL ELECTRIC CAPITAL
                                          CORPORATION, as Co-Documentation Agent


                                          By. __________________________________
                                              Name:
                                              Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                        REVOLVING CREDIT LENDERS, TRANCHE A EURO
                        TERM LENDERS AND TRANCHE A U.S. TERM LENDERS

                                  ______________________________________________
                                  [Print Name of Financial Institution]

                                  By ___________________________________________
                                     Name:
                                     Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                             TRANCHE B TERM LENDERS

                                   _____________________________________________
                                   [Print Name of Financial Institution]

                                   By __________________________________________
                                      Name:
                                      Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                 ISSUING BANKS

                                          WELLS FARGO BANK TEXAS, N.A.

                                          By ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                          CREDIT SUISSE FIRST BOSTON

                                          By ___________________________________
                                             Name:
                                             Title:

                                          By ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                 SWING LINE BANK

                                          WELLS FARGO BANK TEXAS, N.A.

                                          By ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                    CONSENT

                                                       Dated as of June 30, 2003

     Each of the undersigned as a Loan Party under the Credit Agreement referred
to in the foregoing Amendment No. 5 and as Grantor under the Security Agreement
dated as of April 10, 2001 (as amended, supplemented or otherwise modified from
time to time, the "Security Agreement") in favor of the Collateral Agent, for
its benefit and the benefit of the Lenders party to the Credit Agreement
referred to in the foregoing Amendment No. 5, hereby consents to such Amendment
No. 5 and hereby confirms and agrees that (a) notwithstanding the effectiveness
of such Amendment No. 5, each Loan Document is, and shall continue to be, in
full force and effect and is hereby ratified and confirmed in all respects,
except that, on and after the effectiveness of such Amendment No. 5, each
reference in each Loan Document to the "Credit Agreement", "thereunder",
"thereof" or words of like import shall mean and be a reference to the Credit
Agreement, as amended by such Amendment No. 5, and (b) the Collateral Documents
to which such Grantor is a party and all of the Collateral described therein do,
and shall continue to, secure the payment of all of the Secured Obligations (in
each case, as defined therein).

                                 DEG ACQUISITIONS, LLC

                                 By: FIRST RESERVE FUND VIII, L.P.,
                                     a Delaware limited partnership, its Manager
                                     By: FIRST RESERVE GP VIII, L.P.,
                                         a Delaware limited partnership,
                                         its general partner
                                         By: FIRST RESERVE CORPORATION,
                                             a Delaware corporation, its general
                                             partner

                                         By: ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                          DRESSER HOLDINGS, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                                          DRESSER INTERNATIONAL, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                                          DRESSER RE, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                                          DRESSER RUSSIA, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                                          LVF HOLDING CORPORATION

                                          By ___________________________________
                                             Name:
                                             Title:

                                          MODERN ACQUISITION, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement

<PAGE>

                                          DRESSER ENTECH, INC.

                                          By ___________________________________
                                             Name:
                                             Title:

                                          RING-O VALVE, INCORPORATED

                                          By ___________________________________
                                             Name:
                                             Title:

                            Amendment No. 5 to the
                           Dresser Credit Agreement