<PAGE>

                                                                  EXHIBIT 10.40

                                  AMENDMENT NO. 1


     THIS AMENDMENT NO. 1 (this "AMENDMENT"), dated as of July 22, 1997, among
R. J. Tower Corporation, a Michigan corporation (the "COMPANY"), the various
financial institutions that are or may become parties to the Credit Agreement
described hereinbelow (individually, a "LENDER" and collectively, the "LENDERS")
and Bank of America National Trust and Savings Association, as agent for the
Lenders (in such capacity, the "AGENT"), is made pursuant to Section 10.1 of
that certain Credit Agreement, dated as of April 18, 1997 (as amended or
modified and in effect on the date hereof, the "EXISTING CREDIT AGREEMENT" and,
as amended or otherwise modified in this Amendment, the "AMENDED CREDIT
AGREEMENT"; capitalized terms used but not defined herein having the same
respective meanings as in the Amended Credit Agreement), among the Company, the
Lenders and the Agent.

                                     WITNESSETH:

     WHEREAS, the Company has requested that the Lenders amend the Existing
Credit Agreement in the manner hereinafter appearing; and, subject to the terms
and conditions set forth herein, the Lenders have agreed to so amend the
Existing Credit Agreement;

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto, intending to be
legally bound, hereby agree as follows:

                               ARTICLE 1. - AMENDMENTS

     1.1.   Section 2.16.1(b)(ii) of the Existing Credit Agreement is hereby
amended by inserting the following proviso immediately before the final period
thereof:

     ", PROVIDED that nothing in this CLAUSE (ii) shall release any LC
     Issuer from its obligation to Issue any Standby Letter of Credit to
     support Existing IRBs having the terms and conditions specified in the
     indenture governing such Existing IRBs"

     1.2.   Section 2.16.1(c)(ii) of the Existing Credit Agreement is hereby
amended by inserting the phrase "in the case of Letters of Credit other than
Standby Letters of Credit supporting Existing IRBs," immediately after the
letter "(x)" in the third line thereof.

<PAGE>

     1.3.   Section 7.8(f) of the Existing Credit Agreement is hereby amended by
deleting the last word "and" therefrom.

     1.4.   Section 7.8(g) of the Existing Credit Agreement is hereby amended by
deleting the final period and substituting the phrase "; and" in lieu thereof.

     1.5.   The following new clause (h) is hereby added to Section 7.8 of the
Existing Credit Agreement:

            (h)    Guaranty Obligations of (i) the Company, (ii) Domestic
     Subsidiaries or (iii) Foreign Subsidiaries that are Material
     Subsidiaries but not Foreign 956 Subsidiaries, in each case with
     respect to obligations of the Parent under any Approved Parent Debt
     and, in the case of subordinated Approved Parent Debt, where such
     Guaranty Obligations are similarly subordinated to the reasonable
     satisfaction of the Agent, and only where such Person has executed and
     delivered a Guaranty to the Agent.
     
     1.6.   Section 7.11(d) of the Existing Credit Agreement is hereby amended
by deleting the last word "and" therefrom.

     1.7.   Section 7.11(e) of the Existing Credit Agreement is hereby amended
by deleting the final period and substituting the phrase "; and" in lieu
thereof.

     1.8.   The following new clause (f) is hereby added to Section 7.11 of the
Existing Credit Agreement:

            (f)    may declare and pay Debt Service Dividends.

     1.9.   Section 7.15(c) of the Existing Credit Agreement is hereby amended
in its entirety to read as follows:

            (c)    the Leverage Ratio on the last day of any fiscal quarter
     for the Reference Period then ended to be more than the applicable
     ratio set forth against the applicable period below:
<TABLE>
<CAPTION>
                    Period
                    ------
            From                  To            Maximum Ratio
            ----                  --            -------------
     <S>                  <C>                   <C>
     Closing Date         December 30, 1999      4.50 to 1.00
     December 31, 1999    December 30, 2000      4.25 to 1.00
     December 31, 2000    thereafter             4.00 to 1.00
</TABLE>

                                     -2-
<PAGE>

     1.10.  Section 7.15 of the Existing Credit Agreement is hereby amended by
adding a new clause (d) to the end thereof:

            (d)    the Senior Leverage Ratio on the last day of any fiscal
     quarter for the Reference Period then ended to be more than the
     applicable ratio set forth against the applicable period below:
<TABLE>
<CAPTION>
                    Period
                    ------
            From                To               Maximum Ratio
            ----                --               -------------
     <S>                  <C>                    <C>
     Closing Date         December 30, 1999      3.50 to 1.00
     December 31, 1999    December 30, 2000      3.25 to 1.00
     December 31, 2000    thereafter             3.00 to 1.00
</TABLE>

     1.11.  Section 10.8(a) of the Existing Credit Agreement is hereby amended
by inserting the parenthetical "(PROVIDED that the minimum principal or face
amount of an assignment and delegation to an existing Lender shall be
$5,000,000)" immediately after the amount "$10,000,000" in the fourteenth line
thereof.

     1.12.  The definition of "EBITDA" in Schedule 1.1 of the Existing Credit
Agreement is hereby amended by inserting the phrase "or the Senior Leverage
Ratio" immediately after the phrase "the Leverage Ratio" in the sixth line
thereof.

     1.13.  Schedule 1.1 of the Existing Credit Agreement is hereby amended by
adding the following new definitions thereto in the appropriate alphabetical
order:
 
            "APPROVED PARENT DEBT" means any unsecured Indebtedness issued
     by the Parent, the proceeds of which are applied to the prepayment of
     the Revolving Loans, which in each case has no scheduled payments of
     principal before April 18, 2004 and which contains terms and
     conditions which are acceptable to the Agent in its reasonable
     discretion (including terms and conditions with respect to amounts,
     maturities, covenants, defaults, remedies and subordination).

            "DEBT SERVICE DIVIDENDS" means cash dividends declared and made
     by the Company to the Parent in such amounts and to the extent
     necessary to allow the Parent to make any regularly scheduled payment
     of interest or the payment of principal at maturity in respect of any
     Approved Parent Debt if and to the extent that such payment is not
     prohibited at such time by the subordination provisions or other
     applicable terms of such Approved Parent Debt or any instrument
     governing such Approved Parent Debt.

                                       -3-
<PAGE>

            "SENIOR LEVERAGE RATIO" for any Reference Period means the
     ratio of (x) total Indebtedness of the Parent and its Subsidiaries,
     excluding any Subordinated Indebtedness, Approved Parent Debt which is
     subordinated in right of payment to the Obligations and related
     Guaranty Obligations on the last day of such period to (y) EBITDA for
     such period.

                               ARTICLE 2. - CONDITIONS 

     2.1.   This Amendment shall become effective as of the date hereof on the
date (the "AMENDMENT EFFECTIVE DATE") that the Agent shall have received each of
the following, in form and substance satisfactory to it:

            (a)    counterparts hereof executed by the parties hereto;

            (b)    a certificate, dated as of the Amendment Effective Date,
     of the Secretary or Assistant Secretary of each Account Party and each
     Guarantor as to (i) resolutions of its Board of Directors then in full
     force and effect authorizing the execution and delivery of this
     Amendment, (ii)  the incumbency and signatures of its officers signing
     this Amendment, and (iii) no amendments or other modifications to its
     articles or certificate of incorporation and by-laws having occurred
     since the date that the certified copies of such documents were
     delivered by such Person pursuant to Section 4.1(c)(i) of the Existing
     Credit Agreement; and

            (c)    a certificate, dated as of the Amendment Effective Date,
     of an authorized officer of the Company as to (i) no Default or Event
     of Default shall have occurred and be continuing as of the Amendment
     Effective Date after giving effect to this Amendment,  (ii) the
     correctness of the representations and warranties contained in the
     Credit Documents in all material respects as of the Amendment
     Effective Date after giving effect to this Amendment, and (iii) the
     satisfaction of each of the conditions precedent contained in this
     Article II.

     2.2. The Agent agrees to notify the Company and the Lending Parties of such
Amendment Effective Date promptly after such Amendment Effective Date occurs.

                                 ARTICLE 3. - GENERAL

     3.1.   To induce the Agent and the Lending Parties to enter into this
Amendment, the Company warrants to the Agent and each Lending Party that: (a)
the warranties contained in the Credit Documents, as amended by the Amendment,
are true and correct in all material respects as of the date hereof with the
same effect as though made on the

                                       -4-
<PAGE>

date hereof; (b) after giving effect to this Amendment, no Event of Default 
or Default exists; (c) this Amendment has been duly authorized by all 
necessary corporate proceedings and duly executed and delivered by each 
Account Party and each Guarantor, and the Amended Credit Agreement and each 
of the other Credit Documents are the legal, valid and binding obligations of 
the applicable Credit Party or Guarantor, enforceable against such Credit 
Party or Guarantor in accordance with their respective terms, except as 
enforceability may be limited by bankruptcy, insolvency or other similar laws 
of general application affecting the enforcement of creditors' rights or by 
general principles of equity; and (d) no consent, approval, authorization, 
order, registration or qualification with any Governmental Authority or 
securities exchange is required for, and in the absence of which would 
adversely affect, the legal and valid execution and delivery or performance 
by any Account Party or any Guarantor of this Amendment or the performance by 
any Credit Party or any Guarantor of the Amended Credit Agreement or any 
other Credit Document to which they are party.

     3.2.   This Amendment may be executed in any number of counterparts and by
the different parties on separate counterparts and each such counterpart shall
be deemed to be an original, but all such counterparts shall together constitute
but one and the same Amendment.

     3.3.   Except as specifically provided above, the Existing Credit Agreement
and the other Credit Documents shall remain in full force and effect and are
hereby ratified and confirmed in all respects.  The execution, delivery, and
effectiveness of this Amendment shall not, except as expressly provided herein,
operate as a waiver of any right, power, or remedy of the Agent or any Lending
Party under the Existing Credit Agreement or any of the other Credit Documents,
nor constitute a waiver or modification of any provision of any of the other
Credit Documents.

     3.4.   On and after the Amendment Effective Date, each reference in the
Existing Credit Agreement and related documents to "Credit Agreement," "this
Agreement" or words of like import, shall, unless the context otherwise
requires, be deemed to refer to the Amended Credit Agreement.

     3.5.   The Company agrees to pay on demand all reasonable costs and
expenses incurred at any time by the Agent (including the reasonable attorney
fees and expenses for the Agent, including the allocated cost of internal
counsel) in connection with the preparation, negotiation, execution and
administration of this Amendment and all other instruments or documents provided
for herein or delivered or to be delivered hereunder or in connection herewith.

                                       -5-
<PAGE>

     3.6.   This Amendment shall be binding upon shall inure to the benefit of
the parties hereto and their respective successors and assigns as provided in
the Amended Credit Agreement.


                                *   *   *   *   *

                                       -6-
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed by their respective officers thereunto duly authorized as of the day
and year first above written.

                    
                          R. J. TOWER CORPORATION,
                          a Michigan corporation
                    
                    
                    
                          By:    /s/ Carl E. Nelson
                                 ---------------------
                          Name:  Carl E. Nelson
                                 ---------------------
                          Title: Vice President       
                                 ---------------------
                    
                    
                          R. J. TOWER CORPORATION,
                          an Indiana corporation
                    
                    
                    
                          By:    /s/ Carl E. Nelson
                                 ---------------------
                          Name:  Carl E. Nelson
                                 ---------------------
                          Title: Vice President
                                 ---------------------
                    
                          R. J. TOWER CORPORATION,
                          a Kentucky corporation
                    
                    
                    
                          By:    /s/ Carl E. Nelson
                                 ---------------------
                          Name:  Carl E. Nelson
                                 ---------------------
                          Title: Vice President
                                 ---------------------
                    
                                       S1
<PAGE>

                          BANK OF AMERICA NATIONAL TRUST AND SAVINGS
                          ASSOCIATION, as Agent
                    
                    
                    
                          By:    /s/ Lynn Stetson
                                 ---------------------
                          Name:  Lynn Stetson
                                 ---------------------
                          Title: Managing Director
                                 ---------------------
                    
                    
                          BANK OF AMERICA NATIONAL TRUST AND SAVINGS
                          ASSOCIATION, as a Lender, LC Issuer and
                          Swingline Lender
                    
                    
                          By:    /s/ Lynn Stetson
                                 ---------------------
                          Name:  Lynn Stetson
                                 ---------------------
                          Title: Managing Director
                                 ---------------------
                    
                    
                                       S2
<PAGE>

                          THE BANK OF NOVA SCOTIA
                    
                    
                          By:    /s/ J. R. Trimble
                                 ---------------------------
                          Name:  J. R. Trimble
                                 ---------------------------
                          Title: Senior Relationship Manager
                                 ---------------------------

                                       S3
<PAGE>

                          BANKERS TRUST COMPANY
                     
                    
                          By:    /s/ Mary Jo Jolly
                                 ---------------------------
                          Name:  Mary Jo Jolly
                                 ---------------------------
                          Title: Assistant Vice President
                                 ---------------------------


                                       S4
<PAGE>

                          THE CHASE MANHATTAN BANK
                    
                    
                          By:    /s/ Andres G. Kalnins
                                 ---------------------------
                          Name:  Andres G. Kalnins
                                 ---------------------------
                          Title: Vice President
                                 ---------------------------


                                       S5
<PAGE>

                          COMERICA BANK
                    

                          By:    /s/ Steven P. Davis
                                 ---------------------------
                          Name:  Steven P. Davis
                                 ---------------------------
                          Title: Assistant V.P.
                                 ---------------------------


                                       S6
<PAGE>

                          FIRST BANK NATIONAL ASSOCIATION
                    
                    
                          By:    /s/ Mark R. McDonald
                                 ---------------------------
                          Name:  Mark R. McDonald
                                 ---------------------------
                          Title: Vice President
                                 ---------------------------


                                       S7
<PAGE>
                          THE FIRST NATIONAL BANK OF CHICAGO
                    
                    
                          By:    /s/ Krys Szremski
                                 ---------------------------
                          Name:  Krys Szremski
                                 ---------------------------
                          Title: V.P.
                                 ---------------------------


                                       S8
<PAGE>
                          ABN AMRO BANK N.V.
                    
                    
                          By:    /s/ Peter L. Eaton
                                 ---------------------------
                          Name:  Peter L. Eaton
                                 ---------------------------
                          Title: Vice President
                                 ---------------------------




                          By:    /s/ John P. Richardson
                                 ---------------------------
                          Name:  John P. Richardson
                                 ---------------------------
                          Title: Asst. Vice President
                                 ---------------------------


                                       S9
<PAGE>


                                 CAISSE NATIONALE DE CREDIT AGRICOLE

                                            
                                  By:    /s/ Dean Balice
                                       -------------------------
                                  Name:  Dean Balice
                                       -------------------------
                                  Title: Senior Vice President
                                       -------------------------


                                       S10
<PAGE>

                                 CIBC INC.
                           
       
                                 By:    
                                        ---------------------------
                                 Name:  
                                        ---------------------------
                                 Title: 
                                        ---------------------------
  
                                       S11
<PAGE>
       
                                 CREDIT LYONNAIS CHICAGO BRANCH
                           
                           
                                 By:    /s/ Michel Buysschaert
                                        ---------------------------
                                 Name:  Michel Buysschaert
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------

                                       S12
<PAGE>

                                 THE DAI-ICHI KANGYO BANK, LTD.,
                                 CHICAGO BRANCH
                           
                           
                                 By:    /s/ Seiichiro Ino
                                        ---------------------------
                                 Name:  Seiichiro Ino
                                        ---------------------------
                                 Title: Vice President
                                        ----------------------------

                                       S13
<PAGE>
     
                                 DRESDNER BANK AG NEW YORK AND
                                 GRAND CAYMAN BRANCHES
                           
                           
                                 By:    /s/ Christopher E. Sarisky
                                        ---------------------------
                                 Name:  Christopher E. Sarisky
                                        ---------------------------
                                 Title: Assistant Treasurer
                                        ---------------------------


                                 By:    /s/ John W. Sweeney
                                        ---------------------------
                                 Name:  John W. Sweeney
                                        ---------------------------
                                 Title: Assistant Vice President
                                        ---------------------------

                                      S14
<PAGE>

                                 KEYBANK NATIONAL ASSOCIATION
                           
                           
                                 By:    /s/ Matthew P. Touhey
                                        ---------------------------
                                 Name:  Matthew P. Touhey
                                        ---------------------------
                                 Title: Asst. Vice President
                                        ---------------------------

                                       S15
<PAGE>

                                 ROYAL BANK OF CANADA
                           
                           
                                 By:    /s/ Patrick K. Shields
                                        ---------------------------
                                 Name:  Patrick K. Shields
                                        ---------------------------
                                 Title: Manager, Corporate Banking
                                        ---------------------------

                                       S16
<PAGE>

                                 THE BANK OF NEW YORK 
       
                           
                                 By:    /s/ Richard A. Raffetto
                                        ---------------------------
                                 Name:  Richard A. Raffetto
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------

                                       S17
<PAGE>

                                 THE BANK OF TOKYO-MITSUBISHI, LTD.,
                                 CHICAGO BRANCH
                           
                           
                                 By:    /s/ Hajme Watanabe
                                        ---------------------------
                                 Name:  Hajme Watanabe
                                        ---------------------------
                                 Title: Deputy General Manager
                                        ---------------------------
 

                                       S18
<PAGE>

                                 BANQUE NATIONALE DE PARIS
                           
                           
                                 By:    /s/ Arnaud Collin du Bocage
                                        ---------------------------
                                 Name:  Arnaud Collin du Bocage
                                        ---------------------------
                                 Title: Executive Vice President 
                                        and General Manager
                                        ---------------------------

                                       S19
<PAGE>

                     
                                 COOPERATIEVE CENTRALE RAIFFEISEN-BOERENLEENBANK
                                 B.A. "RABOBANK NEDERLAND", NEW YORK BRANCH
                           
                           
                                 By:    
                                        ---------------------------
                                 Name:  
                                        ---------------------------
                                 Title: 
                                        ---------------------------


                                 By: 
                                        ---------------------------
                                 Name:
                                        ---------------------------
                                 Title:
                                        ---------------------------
       
                                       S20
<PAGE>
                    
                                 FIRST UNION NATIONAL BANK
                                 (formerly known as First Union National Bank
                                 of North Carolina)
                           
                           
                                 By:    /s/ Mark M. Hardin
                                        ---------------------------
                                 Name:  Mark M. Hardin
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
       
                                       S21
<PAGE>
               
                                        THE FUJI BANK, LIMITED
                                  
                                  
                                 By:    /s/ Peter L. Chinnici
                                        ---------------------------
                                 Name:  Peter L. Chinnici
                                        ---------------------------
                                 Title: Joint General Manager
                                        ---------------------------

                                       S22
<PAGE>

                           
                                 ISTITUTO BANCARIO SAN PAOLO DI TORINO
                                 S.P.A.
                           
                           
                                 By:    
                                        ---------------------------
                                 Name:  
                                        ---------------------------
                                 Title: 
                                        ---------------------------
       
       
                                 By: 
                                        ---------------------------
                                 Name:
                                        ---------------------------
                                 Title:
                                        ---------------------------

                                       S23

<PAGE>

                                 THE LONG-TERM CREDIT BANK OF JAPAN, LTD.
                           
                           
                                 By:    /s/ Mark A. Thompson
                                        ---------------------------
                                 Name:  Mark A. Thompson
                                        ---------------------------
                                 Title: Senior Vice President and
                                        Treasurer
                                        ---------------------------

                                       S24
<PAGE>
                    
                                 THE MITSUBISHI TRUST & BANKING CORPORATION,
                                 CHICAGO BRANCH
                           
                           
                                 By:    /s/ Mr. Hiroaki Tsuchiya
                                        ---------------------------
                                 Name:  Mr. Hiroaki Tsuchiya
                                        ---------------------------
                                 Title: Chief Manager
                                        ---------------------------

                                       S25
<PAGE>


                    
                                 THE SANWA BANK, LIMITED, CHICAGO BRANCH
                           
                           
                                 By:    /s/ Richard H. Ault
                                        ---------------------------
                                 Name:  Richard H. Ault
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------

                                       S26
<PAGE>

                    
                                 THE SUMITOMO BANK, LIMITED, CHICAGO
                                 BRANCH
                           
                           
                                 By:    /s/ John H. Kemper
                                        ---------------------------
                                 Name:  John H. Kemper
                                        ---------------------------
                                 Title: Senior Vice President
                                        ---------------------------

                                       S27
<PAGE>

Each of the undersigned hereby consents to the Amendment, ratifies and confirms
all terms and provisions of the Guaranty dated as of April 18, 1997 (the
"GUARANTY") by the undersigned in favor of the Secured Parties and agrees that
the Guaranty is and remains in full force and effect.

                    
                                 R. J. TOWER CORPORATION,
                                 a Michigan corporation
                           
                           
                           
                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 R. J. TOWER CORPORATION,
                                 an Indiana corporation
                           
                           

                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 R. J. TOWER CORPORATION,
                                 a Kentucky corporation


                           
                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 TOWER AUTOMOTIVE, INC.


                           
                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------

                                       S28
<PAGE>

                           
                                 EDGEWOOD MANUFACTURING CORP.
                           
                           
                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 KALAMAZOO STAMPING AND DIE COMPANY
                           
                           

                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
       
                           
                                 TOWER AUTOMOTIVE DELAWARE, INC.
                           
                           

                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 TOWER AUTOMOTIVE PRODUCTS COMPANY, INC.
                           
                           

                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
                                 Name:  Carl E. Nelson
                                        ---------------------------
                                 Title: Vice President
                                        ---------------------------
                           
                           
                                 TRYLON CORPORATION
                           


                                 By:    /s/ Carl E. Nelson
                                        ---------------------------
       
                                      S29
<PAGE>
     
                                        Name:  Carl E. Nelson
                                        ---------------------------
                                        Title: Vice President
                                        ---------------------------
                           
       
                                      S30