FIRST AMENDMENT

Exhibit 10.9

FIRST AMENDMENT

     FIRST AMENDMENT, dated as of December 22, 2003 (this “Amendment”), to the Credit Agreement, dated as of June 20, 2003 (as amended from time to time, the “Credit Agreement”), among UNITED COMPONENTS, INC., a Delaware corporation (the “Borrower”), the several banks and other financial institutions or entities from time to time parties to the Credit Agreement (the “Lenders”), LEHMAN BROTHERS INC. and J.P. MORGAN SECURITIES INC., as joint advisors, joint lead arrangers and joint bookrunners (in such capacity, the “Joint Lead Arrangers”), JPMORGAN CHASE BANK, as syndication agent (in such capacity, the “Syndication Agent”), ABN AMRO BANK N.V., CREDIT LYONNAIS, NEW YORK BRANCH, FLEET NATIONAL BANK and GENERAL ELECTRIC CAPITAL CORPORATION, as co-documentation agents (in such capacity, the “Co-Documentation Agents”), and LEHMAN COMMERCIAL PAPER INC., as administrative agent (in such capacity, the “Administrative Agent”).

W I T N E S S E T H :

     WHEREAS, pursuant to the Credit Agreement, the Lenders have agreed to make, and have made, certain loans and other extensions of credit to the Borrower;

     WHEREAS, Borrower has requested certain amendments to the Credit Agreement as more fully set forth herein; and

     WHEREAS, the Lenders are willing to agree to such amendments on the terms and subject to the conditions contained in this Amendment.

     NOW, THEREFORE, the parties hereto hereby agree as follows:

     SECTION 1. Defined Terms. Unless otherwise defined herein, terms defined in the Credit Agreement and used herein shall have the meanings given to them in the Credit Agreement.

     SECTION 2. Amendments to Subsection 1.1. (a) The definitions of “Applicable Margin”, “Commitment”, “Facility”, “Term Lenders” and “Term Loans” contained in Section 1.1 of the Credit Agreement are hereby amended in their respective entireties to read as follows:

     “Applicable Margin”: for each Type of Loan under each Facility, the rate per annum set forth opposite such Facility under the relevant column heading below:

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provided, that (i) on and after the first Adjustment Date occurring after the completion of two full fiscal quarters of the Borrower after the Closing Date, the Applicable Margins with respect to Revolving Credit Loans, Swing Line Loans and Tranche A Term Loans will be determined pursuant to the Pricing Grid and (ii) if, at any time after the completion of two full fiscal quarters of the Borrower after the First Amendment Effective Date, the Consolidated Leverage Ratio measured as of the last day of the most recently ended fiscal quarter of the Borrower is less than 4.00:1.00, the Applicable Margins with respect to Tranche C Term Loans shall be reduced, on the date financial statements with respect to such fiscal quarter are delivered to the Lenders in accordance with Section 6.1, to 1.50%, in the case of Base Rate Loans, and 2.50%, in the case of Eurodollar Loans.

     “Commitment”: with respect to any Lender, each of the Tranche A Term Loan Commitment, the Tranche C Term Loan Commitment and the Revolving Credit Commitment of such Lender.

     “Facility”: each of (a) the Tranche A Term Loan Commitments and the Tranche A Term Loans made thereunder (the “Tranche A Term Loan Facility”), (b) the Tranche C Term Loan Commitments and the Tranche C Term Loans made thereunder (the “Tranche C Term Loan Facility”) and (c) the Revolving Credit Commitments and the extensions of credit made thereunder (the “Revolving Credit Facility”).

     “Term Loan Facilities”: the collective reference to the Tranche A Term Loan Facility and the Tranche C Term Loan Facility.

     “Term Loan Lenders”: the collective reference to the Tranche A Term Loan Lenders and the Tranche C Term Loan Lenders.

     “Term Loans”: the collective reference to the Tranche A Term Loans and the Tranche C Term Loans.

     (b)     The definition of “Interest Period” in Section 1.1 of the Credit Agreement is hereby amended by replacing the words “Tranche B” therein with the words “Tranche C”.

     (c)     Section 1.1 of the Credit Agreement is hereby amended by inserting the following new definitions in the appropriate alphabetical order:

     “First Amendment”: the First Amendment, dated as of December 22, 2003, to this Agreement.

     “First Amendment Effective Date”: as defined in Section 10 of the First Amendment, which date is December 22, 2003.

     “Tranche C Lender Addendum”: a Tranche C Lender Addendum, substantially in the form of Exhibit A to the First Amendment, to be executed and

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delivered by such Lender on the First Amendment Effective Date as provided in Section 8 of the First Amendment.

     “Tranche C Term Loan”: as defined in Section 2.1.

     “Tranche C Term Loan Commitment”: as to any Lender, the obligation of such Lender, if any, to make a Tranche C Term Loan to the Borrower hereunder on the First Amendment Effective Date in a principal amount not to exceed the amount set forth under the heading “Tranche C Term Loan Commitment” opposite such Lender’s name on Schedule 1 to the Tranche C Lender Addendum delivered by such Lender, or, as the case may be, in the Assignment and Acceptance pursuant to which such Lender became a party hereto. The original aggregate amount of the Tranche C Term Loan Commitments is $297,000,000.

     “Tranche C Term Loan Lender”: each Lender that has a Tranche C Term Loan Commitment or that holds a Tranche C Term Loan.

     “Tranche C Term Loan Percentage”: as to any Tranche C Term Lender at any time, the percentage which such Lender’s Tranche C Term Loan Commitment then constitutes of the aggregate Tranche C Term Loan Commitments (or, at any time after the First Amendment Effective Date, the percentage which the aggregate principal amount of such Lender’s Tranche C Term Loans then outstanding constitutes of the aggregate principal amount of the Tranche C Term Loans then outstanding).

     SECTION 3. Amendment to Section 2.1. Section 2.1 of the Credit Agreement is hereby amended by (a) deleting the word “and” at the end of clause (a) in the first sentence thereof and substituting “,” in lieu thereof and (b) adding the following language immediately after clause (b) thereof:

and (c) the Tranche C Term Lenders severally agree to make term loans (each, a “Tranche C Term Loan”) to the Borrower on the First Amendment Effective Date in an amount for each Tranche C Term Loan Lender not to exceed the Tranche C Term Loan Commitment of such Lender.

     SECTION 4. Amendments to Section 2.3. Section 2.3 of the Credit Agreement is hereby amended by adding a new paragraph (c), as follows:

     (c) The Tranche C Term Loan of each Tranche C Term Loan Lender shall mature in 23 consecutive quarterly installments, commencing on December 31, 2004, each of which shall be in an amount equal to such Lender’s Tranche C Term Loan Percentage multiplied by the amount set forth below opposite such installment:

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     SECTION 5. Amendments to Section 2.18. Section 2.18(a) of the Credit Agreement is hereby amended by replacing the phrase “Tranche B Term Loan Percentages” therein with the phrase “Tranche C Term Loan Percentages”.

     SECTION 6. Amendment to Section 4.16. Section 4.16 of the Credit Agreement is hereby amended by adding immediately at the end thereof the sentence “The proceeds of the Tranche C Term Loans shall be used to prepay the Tranche B Term Loans outstanding on the First Amendment Effective Date.”

     SECTION 7. Amendment to Section 10.6. Section 10.6(c) of the Credit Agreement is hereby amended by replacing the phrase “Tranche B Term Loan Facility” therein with the phrase “Tranche C Term Loan Facility”.

     SECTION 8. Joinder. From and after the First Amendment Effective Date, each Tranche C Term Lender executing and delivering a Tranche C Lender Addendum in the form of Exhibit A hereto shall become a party to the Credit Agreement and have the rights and obligations of a Lender thereunder and under the other Loan Documents and shall be bound by the other provisions thereof.

     SECTION 9. Notice of Borrowing. The Borrower shall give the Administrative Agent irrevocable notice (which notice must