<PAGE>
                             THIRTEENTH AMENDMENT TO
                     AMENDED AND RESTATED CREDIT AGREEMENT,
                AMENDMENT AGREEMENT, AMENDED AND RESTATED PLEDGE
                        AGREEMENT AND SECURITY AGREEMENT


         This Thirteenth Amendment to Amended and Restated Credit Agreement,
Amendment Agreement, Amended and Restated Pledge Agreement and Security
Agreement (this "Amendment") is entered into on July 30, 2002 between Bank One,
NA (successor by merger to Bank One, Michigan), with its main office in Chicago,
Illinois ("Bank One"), PNC Bank, National Association (collectively with Bank
One, the "Banks"), with Bank One as agent for the Banks (the "Agent"), Owosso
Corporation ("Owosso"), Ahab Investment Company, DWZM, Inc. ("DWZM"), SMX
Liquidation Corp., Inc., f/k/a Snowmax Incorporated ("Snowmax"), GBMC, Inc.
("GBMC"), Stature Electric, Inc. ("Stature"), Owosso Motor Group, Inc., AAC
Liquidation Corp., Inc., f/k/a Astro Air Coils, Inc. ("Astro Air") and
Owosso-Delaware, Inc. and f/k/a Cramer Company ("Cramer") (collectively, the
"Borrowers").

                                    RECITALS

         This Amendment is based on the following recitals ("Recitals"), which
are incorporated into and made a part of this Amendment:

         5. The Banks and the Borrowers are parties to an Amended and Restated
Credit Agreement dated as of January 22, 1999, as amended by a First Amendment
to Amended and Restated Credit Agreement dated as of June 14, 2000, a Second
Amendment to Amended and Restated Credit Agreement dated as of September 28,
2000, a Third Amendment to Amended and Restated Credit Agreement, Revolving
Credit Note, Amended and Restated Pledge Agreement and Security Agreement dated
effective as of October 29, 2000, a Fourth Amendment to Amended and Restated
Credit Agreement, Revolving Credit Notes and Security Agreement dated as of
November 30, 2000, a Fifth Amendment to Amended and Restated Credit Agreement,
Revolving Credit Notes, Amended and Restated Pledge Agreement and Security
Agreement dated January 24, 2001, an Amendment Agreement dated February 12, 2001
(the "Amendment Agreement"), a Seventh Amendment to Amended and Restated Credit
Agreement dated as of May 9, 2001, an Eighth Amendment to Amended and Restated
Credit Agreement and Amendment Agreement dated as of July 31, 2001, a Ninth
Amendment to Amended and Restated Credit Agreement and Amendment Agreement dated
January 7, 2002, a Tenth Amendment to Amended and Restated Credit Agreement and
Amendment Agreement dated February 7, 2002, an Eleventh Amendment to Amended and
Restated Credit Agreement and Amendment Agreement dated May 16, 2002 and a
Twelfth Amendment to Amended and Restated Credit Agreement and Amendment
Agreement as of July 8, 2002 (as amended, the "Loan Agreement") and two
Revolving Credit Notes dated May 16, 2002 each running in favor of one of the
Banks (the "Notes") as well as various other documents executed previously,
simultaneously therewith or subsequently (all of the foregoing, including the
Loan Agreement, are collectively referred to as the "Loan Documents").

                                      B-1


<PAGE>


         6. In addition to the Banks and the Borrowers, Motor Products-Ohio
Corporation and Motor Products-Owosso Corporation (the "Motor Products
Entities") were "Borrowers" under the terms of the Loan Agreement, the Amendment
Agreement and the Notes and additionally pledged all of their assets in favor of
the Agent, for the benefit of the Banks, as collateral for all of the Borrowers'
obligations pursuant to the terms of a Security Agreement dated on or about
January 22, 1999, as amended, given by the Motor Products Entities and the
Borrowers in favor of the Agent (the "Security Agreement"), as well as separate
Continuing Security Agreements given by each of the Borrowers, including the
Motor Products Entities, in favor of the Agent. As additional collateral for the
loans provided under the Loan Documents, Owosso pledged all of the stock of the
Motor Products Entities and the other Borrowers (other than Owosso) in favor of
the Agent, for the benefit of the Banks, pursuant to an Amended and Restated
Stock Pledge Agreement dated January 22, 1999, as amended, given by Owosso in
favor of the Agent (the "Stock Pledge Agreement").

         7. Owosso has decided to sell all of the stock of the Motor Products
Entities (the "Stock Sale") pursuant to a Stock Purchase Agreement dated July 8,
2002 among Owosso, the Motor Products Entities and Hathaway Motion Control
Corporation ("Hathaway") (the "Stock Purchase Agreement"). The Borrowers and the
Motor Products Entities have asked the Banks to consent to their entering into
the transactions contemplated by the Stock Purchase Agreement, to release their
liens and security interests against the assets of the Motor Products Entities
as provided in the payoff letter dated of even date herewith and attached hereto
as Exhibit A (the "Payoff Letter") and to otherwise release the Motor Products
Entities from their obligations under the Loan Agreement, the Amendment
Agreement and the Loan Documents in exchange for a payment to be made to the
Banks equal to $11,500,000 and delivery of the other items described in the
Payoff Letter.

         8. To reflect the removal of the Motor Products Entities as borrowers
under the Loan Agreement and the release of the pledge of the Motor Products
Entities' stock under the Stock Pledge Agreement, in connection with the
foregoing, the Borrowers have requested and, subject to the terms hereof, the
Banks have agreed to amend the Loan Agreement, the Stock Pledge Agreement and
the Security Agreement as provided in this Amendment.

                                    AGREEMENT

      Based on the foregoing Recitals (which are incorporated herein as
      representations, warranties, acknowledgments and agreements of the
      parties, as the case may be) and for other good and valuable
      consideration, the receipt and adequacy of which is mutually acknowledged
      by the parties hereto, Borrowers and Banks agree effective upon
      consummation of closing of the Stock Sale as follows:

         N. The Loan Agreement and Amendment Agreement are amended as follows:

                  1.       The "Commitment" of each of the Banks is hereby
         permanently reduced to the following amounts as of the effective date
         of this Agreement: for Bank One, $6,522,727 for PNC, $3,727,273 and
         collectively, $10,250,000. Any borrowings in excess of the lesser of
         (a) the Commitments as in effect from time to time less the total
         amount of L/C Outstandings or (b) the Borrowing Base are immediately
         due and payable.

                                      B-2


<PAGE>


                  2.       Section 2.2(a) of the Loan Agreement is amended and
         restated in its entirety to read as follows:

                           "(a) The Borrowers shall have the right to terminate
                  the Commitments or reduce the commitment amounts for the Banks
                  set forth in the signature pages hereof at any time and from
                  time to time, provided that (i) the Borrowers shall give
                  written notice of such termination or reduction to the Agent
                  (with sufficient executed copies for each Bank) specifying the
                  amount and effective date thereof, (ii) each partial reduction
                  of such commitment amounts shall be in a minimum amount of
                  $100,000 and in an integral multiple of $50,000, (iii) no such
                  termination or reduction shall be permitted with respect to
                  any portion of the Commitments as to which a request for a
                  Borrowing pursuant to Section 2.4 is then pending, and (iv)
                  the Commitments may not be terminated in their entirety if any
                  Loans are then outstanding and the commitment amounts may not
                  be reduced below the principal amount of Loans then
                  outstanding. The Borrowers shall provide written notice
                  hereunder in a form to be agreed upon by the Banks and the
                  Borrowers."

                  3.       Section 2.2(d) of the Loan Agreement is amended and
         restated in its entirety to read as follows:

                           "(d) The Commitments will additionally cumulatively
                  reduce by the following amounts (each a "Mandatory Reduction")
                  at the following times in accordance with the terms of this
                  Section 2.2:

                           Mandatory       Total Cumulative             New
       Date                Reduction          Reduction              Commitment
       ----                ---------          ---------              ---------

     Sept 30, 2002         $250,000            $250,000            $10,000,000

     Oct 30, 2002          $150,000            $400,000             $9,850,000

     Nov 30, 2002          $100,000            $500,000             $9,750,000

                  As part of the calculation of the cumulative reduction, the
         Commitments will reduce on a dollar for dollar basis by 100% of the net
         proceeds (net only of reasonable costs of closing pursuant to sale
         terms and conditions acceptable to the Banks in their reasonable
         discretion) promptly upon the Borrowers' receipt thereof of the sale of
         any of the assets of the Borrowers, including without limitation the
         real estate owned by Snowmax and Cramer, and by 100% of the face value
         of any Letter of Credit or full amount of any cash deposit related
         thereto returned to either of the Banks promptly upon the Borrowers'
         receipt thereof."

         O. The definition of "Additional Amount" in Section 1.1 of the Loan
Agreement is amended and restated in its entirety to read as follows:


                                      B-3



<PAGE>


""Additional Amount" means $6,985,000, less the following amounts immediately
upon the Borrowers' receipt thereof: 100% of the net proceeds (net only of
reasonable costs of closing pursuant to sale terms and conditions acceptable to
the Banks in their reasonable discretion) of the sale of any of the assets of
the Borrowers, including without limitation the real estate owned by Snowmax and
Cramer; the face value of any Letter of Credit or full amount of any cash
deposit related thereto returned to either of the Banks; and the amount of any
reduction in the Commitments permitted or required under Section 2(a) and/or
2(d) of the Loan Agreement."

         P. The Borrowers have advised the Banks that following Owosso's sale of
the stock of the Motor Products Entities they may be unable to comply with the
financial covenants set forth in Section 7(f) of the Amendment Agreement. The
Borrowers have requested that the Banks agree to amend Section 7(f) of the
Amendment Agreement to delete all financial covenants covering the period after
the sale of the stock of the Motor Products Entities and add a new financial
covenant based on the EBITDA of Stature. The Banks have agreed to discuss such
an amendment with the Borrowers but as of the date of this Amendment the
Borrowers have not provided the Banks with either proposed covenant formulas or
levels or any of the financial materials needed to permit the Banks to evaluate
the request. Until such time as the Borrowers and the Banks may come to an
agreement with respect to modifications to Section 7(f) of the Amendment
Agreement and such agreement is reduced to writing and signed by each of the
Borrowers, the Banks and the Agent, Section 7(f) remains in full force and
effect notwithstanding the sale of the stock of the Motor Products Entities.

         Q. The Agent has advised the Borrowers that a review of its internal
books and records indicates that since February 1, 2001 interest has been
accrued on a year of 360 days rather than a year of 365 or 366 days as provided
in the Loan Documents. Recalculating the interest using the correct year basis
results in a $37,796.83 credit due to the Borrowers (the "Interest Credit"). The
Agent will apply the Interest Credit to the August, 2002 interest payment due
from the Borrowers to the Lenders. By signing this Amendment and accepting the
Interest Credit, the Borrowers waive any and all claims they may have with
respect to the Interest Credit.

         R. The Notes are amended and restated in their entireties by the
Amended and Restated Revolving Credit Notes in the form of collective Exhibit B
hereto (the "New Notes").

         S. By signing below, each of the Borrowers (a) agrees that it is
waiving any and all rights it may have against the Motor Products Entities or
either of them for contribution or otherwise under the terms of the Loan
Agreement or the Loan Documents, including, without limitation, rights arising
under Section 8.14 of the Loan Agreement, regardless of what amount, if any, the
Banks may actually receive as a result of the sale of the Motor Products
Entities stock and (b) represents and warrants that the removal of the Motor
Products Entities as Borrowers under the Loan Documents will not materially
adversely affect the remaining Borrowers' ongoing businesses or cause an
inability of the remaining Borrowers to meet their obligations under the Loan
Documents except as set forth in Paragraph C above. From and after the date of
this Amendment, the Motor Products Entities shall no longer be "Borrowers" under
the Loan Agreement or the Amendment Agreement. By signing below, each of the
Motor Products Entities releases any claims it may have against the other
Borrowers arising under or in respect of the Loan Documents.


                                      B-4



<PAGE>


         T. The Stock Pledge Agreement is amended to delete all references to
the Motor Products Entities or their stock.

         U. The Security Agreement is amended to delete all references to the
Motor Products Entities or their assets.

         V. The Banks and the Agent release the Motor Products Entities as
Borrowers under the Loan Documents and from any liability or obligation, whether
by guaranty or otherwise, under the Loan Documents, the Security Agreement or
the Stock Pledge Agreement.

         W. To the extent required under the terms of the Loan Documents, the
Banks consent to the Motor Products Entities and Owosso entering into the Stock
Purchase Agreement and related documents, subject to the requirements set forth
herein and in the Payoff Letter.

         X. Borrowers acknowledge that as an accommodation to Hathaway and the
Motor Products Entities, and in accordance with the terms of the Payoff Letter,
Hathaway will be entitled to maintain all accounts of either of the Motor
Products Entities with either of the Banks (the "Motor Products Accounts") until
August 31, 2002, and that if the Motor Products Accounts are not closed by that
date the Banks may close and cancel them. Until such time as the Motor Products
Accounts are closed, as an inducement to the Banks to maintain the Motor
Products Accounts, the Borrowers acknowledge and agree that they remain jointly
and severally liable to the Banks with respect to any liability the Banks may
incur with respect to the Motor Products Accounts, including adjustments for
returned items, insufficient funds checks, partial credits, provisional credits
and like items and account fees and charges, and agree to indemnify and hold
harmless the Banks with respect to such amounts.

         Y. From and after the date of this Amendment, references in the Loan
Documents (i) to the Loan Agreement, the Stock Pledge Agreement, the Security
Agreement and the Amendment Agreement are to be treated as referring to the Loan
Agreement, the Stock Pledge Agreement, the Security Agreement and the Amendment
Agreement as amended by this Amendment, (ii) to the Notes are to be treated as
referring to the New Notes, and (iii) (iv) to "obligations", "Obligations" and
"liabilities" are to be treated as referring to all indebtedness and obligations
referred to in this Amendment or the Loan Documents.

         Z. Subsequent to execution and delivery of this Amendment, Borrowers
must cause to be executed and delivered to the Banks such financing statements,
resolutions and other agreements that the Banks may reasonably require to
effectuate the transactions contemplated by this Amendment. Borrowers must pay
all costs and expenses (including reasonable attorneys' fees) incurred by the
Banks in connection with this Amendment.


                                      B-5



<PAGE>


         AA. Each Borrower expressly acknowledges and agrees that (i) each
Borrower, jointly, jointly and severally, and severally remains liable for any
and all obligations and indebtedness under the Loan Documents and (ii) except to
the extent heretofore or herein released, all collateral security and security
interests, liens, pledges, and mortgages heretofore or hereafter granted the
Banks including, without limitation, such collateral, security interests, liens,
pledges, and mortgages granted under the Loan Documents, extend to and cover all
of each Borrower's obligations to the Banks, now existing or hereafter arising
including, without limitation, those arising in connection with this Amendment
and under all guaranty agreements now or in the future given by any Borrower in
either Bank's favor, each Borrower's present and future obligations to the Banks
under foreign exchange contracts, derivatives or hedging transactions, including
but not limited to interest rate, commodity, currency, or credit swaps or
options that may be provided from time to time by the Banks to the Borrowers,
all of which security interests, liens, pledges, and mortgages are ratified,
reaffirmed, confirmed and approved.

         BB. Each Borrower represents and warrants to the Banks that:

              (4) (a) The execution, delivery and performance of this Amendment
         by the Borrowers and all agreements and documents delivered by
         Borrowers in connection with this Amendment have been duly authorized
         by all necessary corporate or other organizational action and does not
         and will not require any consent or approval of its stockholders or
         members, violate any provision of any law, rule, regulation, order,
         writ, judgment, injunction, decree, determination or award presently
         in effect having applicability to it or of its articles of
         incorporation, articles of organization, or bylaws, or result in a
         breach of or constitute a default under any indenture or loan or
         credit agreement or any other agreement, lease or instrument to which
         any Borrower is a party or by which it or its properties may be bound
         or affected.

                    (b) No authorization, consent, approval, license, exemption
               of or filing a registration with any court or governmental
               department, commission, board, bureau, agency or instrumentality,
               domestic or foreign, is or will be necessary to the valid
               execution, delivery or performance by Borrowers of this Amendment
               and all agreements and documents delivered in connection with
               this Amendment.

                    (c) This Amendment and all agreements and documents
               delivered by Borrowers in connection with this Amendment are the
               legal, valid and binding obligations of each Borrower enforceable
               against it in accordance with the terms thereof.

              (5) After giving effect to the amendments contained in this
         Amendment, all of the representations and warranties contained in the
         Loan Documents are true and correct in all material respects on and as
         of the date hereof with the same force and effect as if made on and as
         of the date hereof.

              (6) Each Borrower's interim financial statements furnished to the
         Banks, which have been provided through June 23, 2002, fairly present
         such Borrower's financial condition as of such dates and the results
         of such Borrower's operations for the periods indicated. The
         Borrowers' consolidated financial statements have been prepared in
         accordance with generally accepted accounting principles applied on a
         consistent basis, and since the date of the last such financial
         statement there has been no material adverse change in such financial
         condition.


                                      B-6


<PAGE>


         CC. The terms and provisions of this Amendment amend, add to and
constitute a part of the Loan Agreement, the Amendment Agreement and the other
Loan Documents. Except as expressly modified and amended by the terms of this
Amendment, all of the other terms and conditions of the Loan Agreement, the
Amendment Agreement and the other Loan Documents remain in full force and effect
and are ratified, reaffirmed, confirmed, and approved.

         DD. If there is an express conflict between the terms of this Amendment
and the terms of the Loan Agreement or the other Loan Documents, the terms of
this Amendment govern and control.

         EE. This Amendment may be executed in any number of counterparts with
the same effect as if all signatories had signed the same document. All
counterparts must be construed together to constitute one instrument.

         FF. WAIVER OF JURY TRIAL.

              BORROWERS AND BANKS EACH ACKNOWLEDGE THAT THE RIGHT TO A TRIAL BY
JURY IS A CONSTITUTIONAL RIGHT, BUT THAT THE RIGHT MAY BE WAIVED. BORROWERS AND
BANKS EACH KNOWINGLY, VOLUNTARILY, IRREVOCABLY AND WITHOUT COERCION, WAIVE ALL
RIGHTS TO TRIAL BY JURY OF ALL DISPUTES BETWEEN THEM. NEITHER OF THE BANKS NOR
ANY BORROWER SHALL BE DEEMED TO HAVE GIVEN UP THIS WAIVER OF JURY TRIAL UNLESS
THE PARTY CLAIMING THAT THIS WAIVER HAS BEEN RELINQUISHED HAS A WRITTEN
INSTRUMENT SIGNED BY THE OTHER PARTY STATING THAT THIS WAIVER HAS BEEN GIVEN UP.

         GG. RELEASE. AS OF THE DATE HEREOF EACH OF THE BORROWERS REPRESENTS AND
WARRANTS THAT THEY ARE AWARE OF, AND POSSESS, NO CLAIMS OR CAUSES OF ACTION
AGAINST EITHER OF THE BANKS OR THE AGENT. NOTWITHSTANDING THIS REPRESENTATION
AND AS FURTHER CONSIDERATION FOR THE AGREEMENTS AND UNDERSTANDINGS HEREIN, EACH
OF THE BORROWERS INDIVIDUALLY, JOINTLY, SEVERALLY, AND JOINTLY AND SEVERALLY, IN
EVERY CAPACITY, INCLUDING BUT NOT LIMITED TO, AS SHAREHOLDERS, OFFICERS,
PARTNERS, DIRECTORS, INVESTORS, OR CREDITORS OF ANY ONE OR MORE OF THE
BORROWERS, EACH OF ITS EMPLOYEES, AGENTS, EXECUTORS, SUCCESSORS AND ASSIGNS,
HEREBY RELEASES EACH OF THE BANKS AND THE AGENT, THEIR OFFICERS, DIRECTORS,
EMPLOYEES, AGENTS, ATTORNEYS, AFFILIATES, SUBSIDIARIES, SUCCESSORS AND ASSIGNS
FROM ANY LIABILITY, CLAIM, RIGHT OR CAUSE OF ACTION THAT NOW EXISTS, OR
HEREAFTER ARISES, WHETHER KNOWN OR UNKNOWN, ARISING FROM OR IN ANY WAY RELATED
TO FACTS IN EXISTENCE AS OF THE DATE HEREOF. BY WAY OF EXAMPLE AND NOT
LIMITATION, THE FORGOING INCLUDES ANY CLAIMS IN ANY WAY RELATED TO ACTIONS TAKEN
OR OMITTED TO BE TAKEN BY EITHER OF THE BANKS OR THE AGENT UNDER THE LOAN
DOCUMENTS, THE BUSINESS RELATIONSHIP WITH EITHER OF THE BANKS OR THE AGENT AND
ALL OTHER OBLIGATIONS OF ANY NATURE OR KIND OF ANY ONE OR MORE OF THE BORROWERS,
ANY ORAL AGREEMENTS OR UNDERSTANDINGS (ACTUAL OR ALLEGED), ANY BANKING
RELATIONSHIPS THAT ANY ONE OR MORE OF THE BORROWERS HAS OR MAY HAVE HAD WITH
EITHER OF THE BANKS AT ANY TIME AND FOR ANY REASON INCLUDING, BUT NOT LIMITED
TO, DEMAND DEPOSIT ACCOUNTS, OR OTHERWISE, BUT DOES NOT INCLUDE THE BORROWERS'
FUTURE RIGHTS TO RECEIVE LOANS UNDER THE TERMS OF THE LOAN DOCUMENTS, AS AMENDED
BY THIS AGREEMENT, OR AS TO AMOUNTS ON DEPOSIT WITH EITHER OF THE BANKS OR STOCK
CERTIFICATES PLEDGED TO AND HELD BY EITHER OF THE BANKS AS COLLATERAL FOR THE
OBLIGATIONS.

                                      B-7


<PAGE>

<TABLE>
<CAPTION>
BANK ONE, MICHIGAN, f/k/a                                     PNC BANK, NATIONAL ASSOCIATION
NBD BANK, individually and as Agent

<S>                                                           <C>
By: /s/ Patricia S. Carpen                                    By: /s/ Frank P. Devine
    -------------------------                                     -------------------

        Name: Patricia S. Carpen                                      Name: Frank P. Devine

        Title: Vice President                                         Title: Vice President

OWOSSO CORPORATION                                            AHAB INVESTMENT COMPANY

By: /s/ George B. Lemmon, Jr.                                 By: /s/ George B. Lemmon, Jr.
    -------------------------                                     -------------------------

        Name: George B. Lemmon, Jr.                                   Name: George B. Lemmon, Jr.

        Title: President                                              Title: President

DWZM, INC.                                                    SMX LIQUIDATION CORP., INC.

By: /s/ George B. Lemmon, Jr.                                 By: /s/ George B. Lemmon, Jr.
    -------------------------                                     -------------------------

        Name: George B. Lemmon, Jr.                                   Name: George B. Lemmon, Jr.

        Title: President                                              Title: President
</TABLE>



                    [Signatures continued on following page]



                                      B-8

<PAGE>


                    [Signatures continued from previous page]


<TABLE>
<CAPTION>
GBMC, INC.                                                    STATURE ELECTRIC, INC.

<S>                                                           <C>
By: /s/ George B. Lemmon, Jr.                                 By: /s/ George B. Lemmon, Jr.
    -------------------------                                     -------------------------

        Name: George B. Lemmon, Jr.                                   Name: George B. Lemmon, Jr.

        Title: President                                              Title: Vice-President


OWOSSO MOTOR GROUP, INC.                                      AAC LIQUIDATION CORP., INC.

By: /s/ George B. Lemmon, Jr.                                 By: /s/ George B. Lemmon, Jr.
    -------------------------                                     -------------------------

        Name: George B. Lemmon, Jr.                                   Name: George B. Lemmon, Jr.

        Title: President                                              Title: President


OWOSSO-DELAWARE, INC.

By: /s/ George B. Lemmon, Jr.
    -------------------------

        Name: George B. Lemmon, Jr.

        Title: President



ACKNOWLEDGED AND AGREED:


MOTOR PRODUCTS-OWOSSO                                         MOTOR PRODUCTS-OHIO
CORPORATION                                                   CORPORATION

By: /s/ George B. Lemmon, Jr.                                 By: /s/ George B. Lemmon, Jr.
    -------------------------                                     -------------------------

        Name: George B. Lemmon, Jr.                                   Name: George B. Lemmon, Jr.

        Title: Vice-President                                         Title: Vice-President
</TABLE>




                                      B-9