Document:

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                                                                    EXHIBIT 4(s)

                                AMENDMENT NO. 10

                      TENTH AMENDMENT TO THIRD AMENDED AND
                 RESTATED REVOLVING CREDIT AGREEMENT AND CONSENT

         THIS TENTH AMENDMENT, dated as of the 28th day of March, 2001, by and
between Newcor, Inc., a Delaware corporation, of Bloomfield Hills, Michigan
(herein called "Company") and Comerica Bank, a Michigan banking corporation, of
Detroit, Michigan (herein called "Bank");

                                   WITNESSETH:

         WHEREAS, Company and Bank desire to amend that certain Third Amended
and Restated Revolving Credit Agreement dated as of January 15, 1998, entered
into by and between Company and Bank, which was amended by nine amendments
(herein called "Agreement");

         NOW, THEREFORE, it is agreed that the Agreement is amended as follows:

         1. The definition of "Commitment" in Section 1 of the Agreement is
amended to read in its entirety as follows:

                  "Commitment' shall mean the total commitment of Bank to make
         Advances to Company pursuant to this Agreement in the amount of Thirty
         Million Dollars ($30,000,000), subject to reduction as herein
         provided."

         2. The definition of "Base Net Worth" in Section 1 of the Agreement is
amended to read in its entirety as follows:

                  "Base Net Worth' shall mean $1,000,000. On the last day of
         each fiscal quarter of Company (commencing March 31, 2001), Base Net
         Worth shall be increased by an amount equal to 50% of Net Income for
         the fiscal quarter then ended. Such increase shall be effective on the
         last day of the fiscal quarter in which such determination is made. For
         any fiscal quarter with respect to which Net Income is less than zero,
         Net Income shall be deemed to be zero."

         3. Section 6.4 of the Agreement is amended to read in its entirety as
follows:

                  "On a consolidated statement basis, maintain as of the end of
         each fiscal quarter, a Funded Debt to EBITDA Ratio of not more than
         12.0 to 1.0."

         4. Company has informed the Bank that it intends to sell certain assets
and to use the proceeds of the sale all as previously described to the Bank in
writing. The sale and use of proceeds is referred to as the "Transaction". The
Transaction is prohibited by the terms of the Agreement and Company has
requested that the Bank consent to the Transaction. The Bank consents to the
Transaction; provided that the Bank's consent is conditioned upon (a) receipt by
the Bank of evidence satisfactory to the Bank that the Transaction is accretive
to Company on a cashflow basis,

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(b) receipt by the Bank of appraisals of Company's machinery and equipment and
real estate from appraisers acceptable to the Bank on a forced sale liquidation
basis acceptable to the Bank and indicating a value of the appraised assets of
not less than $30,000,000, and (c) such other conditions as may be imposed by
the Bank's credit committees.

         5. Company hereby represents and warrants that, after giving effect to
the amendment contained herein, (a) execution, delivery and performance of this
Amendment and any other documents and instruments required under this Amendment
or the Agreement are within Company's corporate powers, have been duly
authorized, are not in contravention of law or the terms of Company's
Certificate of Incorporation or Bylaws, and do not require the consent or
approval of any governmental body, agency, or authority; and this Amendment and
any other documents and instruments required under this Amendment or the
Agreement, will be valid and binding in accordance with their terms; (b) the
continuing representations and warranties of Company set forth in Sections 5.1
through 5.7 and 5.9 through 5.15 of the Agreement are true and correct on and as
of the date hereof with the same force and effect as made on and as of the date
hereof; (c) the continuing representations and warranties of Company set forth
in Section 5.8 of the Agreement are true and correct as of the date hereof with
respect to the most recent financial statements furnished to the Bank by Company
in accordance with Section 6.1 of the Agreement; and (d) no event of default, or
condition or event which, with the giving of notice or the running of time, or
both, would constitute an event of default under the Agreement, has occurred and
is continuing as of the date hereof.

         6. This Amendment shall be effective upon (a) execution of this
Amendment by Company and Bank (b) execution by the Guarantors of the attached
Acknowledgment, and (c) delivery by Company to Bank of an executed Revolving
Credit Note in the form attached hereto as Exhibit "A".

         7. Except as modified hereby, all of the terms and conditions of the
Agreement shall remain in full force and effect.

         WITNESS the due execution hereof on the day and year first above
written.

COMERICA BANK                           NEWCOR, INC.

By: /s/ Brian E. Marshall              By:   /s/ James J. Connor
    ---------------------------------       ------------------------------------

Its: Vice President                     Its: President & Chief Executive Officer
                                            ------------------------------------

                                        By:  /s/ Thomas D. Parker
                                            ------------------------------------

                                        Its: Vice-President Human Resources &
                                             Secretary
                                            ------------------------------------

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                                 ACKNOWLEDGMENT

         The undersigned accept and agree to the Amendment No. 10 to the Third
Amended and Restated Revolving Credit Agreement and agree to the continued
effectiveness of the Guaranties originally executed and delivered to Comerica
Bank by the undersigned guarantying all obligations of Newcor, Inc. to the Bank.

                                        ROCHESTER GEAR, INC.

                                        By: /s/ James J. Connor
                                           -------------------------------------

                                        Its: President
                                            ------------------------------------

                                        By: /s/ Thomas D. Parker
                                           -------------------------------------

                                        Its: Secretary
                                            ------------------------------------

                                        ENC CORP.

                                        By: /s/ James J. Connor
                                           -------------------------------------

                                        Its: President
                                            ------------------------------------

                                        By: /s/ Thomas D. Parker
                                           -------------------------------------

                                        Its: Secretary
                                            ------------------------------------

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DECO TECHNOLOGIES, INC.                 PLASTRONICS PLUS, INC.

By: /s/ James J. Connor                 By: /s/ James J. Connor
   -------------------------               -------------------------

Its: President                          Its: President
    ------------------------                ------------------------

By: /s/ Thomas D. Parker                By: /s/ Thomas D. Parker
   -------------------------               -------------------------

Its: Secretary                          Its: Secretary
    ------------------------                ------------------------

DECO INTERNATIONAL, INC.                NEWCOR M-T-L, INC.

By: /s/ James J. Connor                 By: /s/ James J. Connor
   -------------------------               -------------------------

Its: President                          Its: President
    ------------------------                ------------------------

By: /s/ Thomas D. Parker                By: /s/ Thomas D. Parker
   -------------------------               -------------------------

Its: Secretary                          Its: Secretary
    ------------------------                ------------------------

TURN-MATIC, INC.                        GRAND MACHINING COMPANY

By: /s/ James J. Connor                 By: /s/ James J. Connor
   -------------------------               -------------------------

Its: President                          Its: President
    ------------------------                ------------------------

By: /s/ Thomas D. Parker                By: /s/ Thomas D. Parker
   -------------------------               -------------------------

Its: Secretary                          Its: Secretary
    ------------------------                ------------------------
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                                   EXHIBIT "A"

                              REVOLVING CREDIT NOTE

                                                               Detroit, Michigan
$30,000,000                                                       March 28, 2001

         On or before the Revolving Credit Maturity Date (which initially is
March 31, 2002), FOR VALUE RECEIVED, NEWCOR, INC., a Delaware corporation
(herein called "Company") promises to pay to the order of COMERICA BANK, a
Michigan banking corporation (herein called "Bank") at its Main Office at 500
Woodward Avenue, Detroit, Michigan, 48226 in lawful money of the United States
of America the indebtedness or so much of the sum of Thirty Million Dollars
($30,000,000) as may from time to time have been advanced and then be
outstanding hereunder pursuant to the Third Amended and Restated Revolving
Credit Agreement dated January 15, 1998, made by and between Company and Bank
(as amended from time to time, herein called "Agreement"), together with
interest thereon as hereinafter set forth.

         Each of the Advances made hereunder shall bear interest at the
Eurodollar-based Rate or the Prime-based Rate as elected by Company or as
otherwise determined under the Agreement.

         Interest on the unpaid balance of all Prime-based Advances shall be
payable quarterly commencing on April 30, 2001 and on the last day of each
quarter thereafter. Interest accruing at the Prime-based Rate shall be computed
on the basis of a 360 day year and assessed for the actual number of days
elapsed, and in such computation effect shall be given to any change in the
Prime-based Rate on the date of such change in the Prime-based Rate.

         Interest on each Eurodollar-based Advance shall be payable on the last
day of the Interest Period applicable thereto. Interest accruing at the
Eurodollar-based Rate shall be computed on the basis of a 360 day year and
assessed for the actual number of days elapsed from the first day of the
Interest Period applicable thereto to but not including the last day thereof.

         From and after the occurrence of any event of default hereunder or
under the Agreement or any event which automatically causes the indebtedness
outstanding hereunder to become immediately due and payable, the indebtedness
outstanding hereunder shall bear interest at Three percent (3%) above the
Prime-based Rate as it may vary from time to time, which interest shall be
payable daily.

         This Note is a note under which advances, repayments and readvances may
be made from time to time, subject to the terms and conditions of the Agreement.
This Note evidences borrowing under, is subject to, is secured in accordance
with, and may be matured under, the terms of the Agreement, to which reference
is hereby made. As additional security for this Note, Company grants

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Bank a lien on all property and assets including deposits and other credits of
the Company, at any time in possession or control of or owing by Bank for any
purpose.

         Company hereby waives presentment for payment, demand, protest and
notice of dishonor and nonpayment of this Note and agrees that no obligation
hereunder shall be discharged by reason of any extension, indulgence, release,
or forbearance granted by any holder of this Note to any party now or hereafter
liable hereon or any present or subsequent owner of any property, real or
personal, which is now or hereafter security for this Note. Any transferees of,
or endorser, guarantor or surety paying this Note in full shall succeed to all
rights of Bank, and Bank shall be under no further responsibility for the
exercise thereof or the loan evidenced hereby. Nothing herein shall limit any
right granted Bank by other instrument or by law.

         This Note is a replacement for a Revolving Credit Note dated January
30, 2001 in the original principal amount of $40,000,000 by Company payable to
Bank.

         All capitalized terms used but not defined herein shall have the
meanings ascribed to them in the Agreement.

                                        NEWCOR, INC.

                                        By: /s/ James J. Connor
                                           -------------------------------------

                                        Its: President & Chief Executive Officer
                                            ------------------------------------

                                        By: /s/ Thomas D. Parker
                                           -------------------------------------

                                        Its: Vice-President of Human Resources
                                             Secretary
                                            ------------------------------------<PAGE>   1
                                                                   EXHIBIT 10(i)
                              EMPLOYMENT AGREEMENT

This Agreement, dated as of the 9th day of August 9, 2000, by and among NEWCOR,
INC., a Delaware corporation (the "Company"), and JAMES J. CONNOR ("Employee")

                              W I T N E S S E T H:

WHEREAS, the Company desires to engage the services of Employee, and Employee is
willing to accept such employment, on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the premises and the mutual undertakings set
forth herein the parties hereto agree as follows:

1.       Employment and Duties; Board Appointment. In accordance with actions
         taken and authorized by the Board of Directors of the Company (the
         "Company Board"), effective August 9, 2000, Employee shall become
         employed and appointed as the President and Chief Executive Officer of
         the Company and shall have the duties and responsibilities commensurate
         with such titles and offices, including, without limitation, all such
         duties and responsibilities as now are or hereafter may be set forth
         with respect to such offices in the by-laws of the Company. The Board
         has also taken the appropriate action to appoint Employee as a director
         of the Company effective August 9, 2000. The Employee shall continue to
         serve as a director as long as elected by the shareholders of the
         Company, except that upon termination for any reason of the Employee
         and upon request by the Board, Employee agrees to resign as a director.
         During the period of his employment hereunder, Employee shall serve as
         an officer of such other affiliates of the Company and in such other
         capacities as he may be reasonably requested by the Company Board and
         shall assume such duties and responsibilities as from time to time may
         be reasonably assigned to him by the Company Board, all without
         additional compensation. Throughout the period of his employment
         hereunder, Employee shall devote his business time, attention, and
         energy on a full-time basis (subject to up to four weeks of vacation to
         be taken at reasonable intervals during the year) exclusively to the
         affairs of the Company and its affiliates.

2.       Term of Employment. The employment of Employee hereunder shall become
         effective on August 9, 2000 and shall continue unless terminated as
         hereinafter provided in Section 10 of this Agreement.

3.       Cash Compensation. As full cash compensation for all services to be
         performed by Employee hereunder, the Company shall pay to Employee the
         following:

                  (a) salary at the rate of $200,000 per year which shall become
         $250,000 per year effective January 1, 2001, (to be reviewed annually
         thereafter by the Company Board), payable at the intervals at which
         other executive officers of the Company are paid;

                  (b) eligibility for an additional incentive bonus (if earned)
         of up to 100% base pay. Such bonus shall be payable after the fiscal
         year-end in accordance with Company policy in an amount determined
         based on performance criteria to be developed by the Compensation
         Committee of the Board and approved by the Board of Directors.

4.       Certain Fringe Benefits. During the period of his employment hereunder,
         the Company will provide Employee with the use of a new American-made
         automobile of Employee's choice (and replace such automobile every two
         years or 50,000 miles, whichever first occurs), maintained, insured,
         and equipped at the Company's expense (subject to a $50.00 per month
         charge to Employee for personal use of the automobile). The Employee's
         selection shall be approved by the Compensation Committee of the Board.

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5.       Other Employee Benefits. During the period of his employment hereunder,
         Employee also shall be entitled to participate in such Company employee
         benefit plans as from time to time are maintained, sponsored, or made
         available by the Company to its employees or its executive employees
         generally (including but not limited to the Company's pension plan,
         401(k) plan, and medical plan), in each case on the same terms and
         subject to the same conditions and limitations generally applicable to
         other executive officers of the Company with respect to participation
         therein.

6.       Certain Expenses. The Company shall pay or reimburse Employee for the
         reasonable travel, entertainment and other incidental expenses
         (including the cost of business publications and professional
         associations) incurred on business of the Company with the approval of
         the Chairman of the Company, and in accordance with the Company's
         practices as in effect during the term of this Agreement as applied to
         executive officers.

7.       Stock Options. As evidenced by that certain Stock Option Agreement to
         between Employee and the Company (the "Option Agreement"), Employee
         shall be granted under the Company's 1996 Employee Incentive Stock Plan
         so-called non-qualified stock options to purchase an aggregate of
         10,000 shares of the common stock of the Company (which options shall
         vest with respect to 2,500 shares per year commencing one year from the
         date of the Option Agreement) on the terms and subject to the
         conditions specified in the Option Agreement.

8.       Other Insurance. The Company shall have the right to purchase
         disability and group life insurance policies (in addition to the policy
         referred to in Section 4 above) on Employee whenever during the period
         of his employment hereunder the Company deems it reasonable to acquire
         such insurance. Employee agrees to cooperate in the acquisition of such
         insurance and to perform all acts necessary and proper in connection
         therewith, including submission to such medical examinations as may be
         required. Any policy owned by the Company may be dealt with in such
         manner as the Company deems appropriate.

9.       Certain Continuing Obligations of Employee. Throughout the period of
         his employment hereunder and for a two (2) year period thereafter,
         Employee agrees to keep confidential all trade secrets, customer lists,
         business strategies, financial and marketing information, and other
         data concerning the private affairs of the Company or any of its
         affiliates made known to or developed by Employee during the course of
         his employment hereunder ("Confidential Information"), not to use any
         Confidential Information or supply Confidential Information to others
         other than in furtherance of the Company's business, and to return to
         the Company upon termination of his employment all copies, in whatever
         form, of all Confidential Information and all other documents relating
         to the business of the Company or any of its affiliates which may then
         be in the possession or under the control of Employee. The obligation
         hereunder of Employee to retain in confidence Confidential Information
         shall not apply to information (i) which at the time of disclosure or
         subsequent thereto becomes part of the public domain without action or
         fault of the Employee, (ii) which is previously known to the Employee
         from sources other than the Company, (iii) which is provided by the
         Company to third parties without restriction, or (iv) which is subject
         to disclosure pursuant to compulsory legal process.

         Employee acknowledges and agrees that any intellectual property of any
         sort developed or invented by Employee while employed by the Company
         (whether or not during work hours) shall be and remain the sole and
         exclusive property of the Company, and Employee shall have no interest
         therein.

         Employee further agrees that, during the period of his employment
         hereunder and for a two year period thereafter, he will make no attempt
         whatsoever to induce or encourage any other employee of the Company or
         any of its affiliates to leave such employment for employment with any
         other entity engaged in any line of business competitive with the
         Company or any of its affiliates.

         At the request of the Company Board, whether or not made during the
         period of his employment hereunder, Employee agrees to execute such
         confidentiality agreements, assignments of intellectual property
         rights, and other documents as hereafter may be reasonably determined
         by the Company Board to be appropriate to carry out the purposes of
         this Section.

10.      Termination of Employment; Effect.

         (a)      Employee's employment hereunder will be terminated in any of
                  the following ways:

                  (i)      Immediately upon the death of the Employee;

                  (ii)     Immediately upon the Employee becoming permanently
                           disabled within the meaning of the Company's long
                           term disability policy as then in effect;
<PAGE>   3

                  (iii)    By the Employee providing 30 days' prior written
                           notice to the Company of his desire to terminate the
                           contract, effective as of the date specified in such
                           notice;

                  (iv)     By the Company, without or with Cause (as hereinafter
                           defined), providing 30 days' prior written notice to
                           the Employee, effective as of the date specified in
                           such notice.

         (b)      Upon the termination of Employee's employment in any of the
                  ways provided in subsection (a), then this Agreement and all
                  rights and obligations of Employee and the Company hereunder
                  (as opposed to rights and obligations under the Option
                  Agreement and under any Company employee benefit plan in which
                  Employee participated) shall terminate and cease immediately,
                  except for (i) Employees obligation to resign from the Board
                  of Directors in accordance with Paragraph 1; (ii) Employee's
                  rights to the payments provided in Section 11 below; and (iii)
                  the rights and obligations set forth in Section 9 above and
                  Section 14 below.

11.      Payments on Termination. Employee shall be entitled to the following
         payments and benefits upon termination of his Employment:

         (a)      If Employee's employment is terminated under Section 10(a)(i)
                  above, or if Employee's employment is terminated by Employee
                  under Section 10(a)(iii) above, or if Employee's employment is
                  terminated for Cause by the Company under Section 10(a)(iv)
                  above, then the cash compensation under Section 3(a) above,
                  and the benefits to which Employee is entitled under Sections
                  4 and 5 above, shall cease on the date of termination of
                  employment.

         (b)      If Employee's employment is terminated under Section 10(a)(ii)
                  above, or by the Company without Cause under Section 10(a)(iv)
                  above, Employee shall be entitled to the cash compensation
                  payable under Section 3(a) above, continuation of the benefits
                  referred to in Sections 4 and 5 above (subject to the
                  provisions below regarding the Company medical plan), for a
                  period of one year following the effectiveness of such
                  termination of employment; and provided, further, that the
                  benefits provided under Section 4 above shall continue for the
                  period determined as aforesaid but not after Employee shall be
                  effectively provided with substantially equivalent benefits by
                  another employer. In the event termination of employment
                  occurs under Section 10(a)(ii) above, the payments made by the
                  Company as aforesaid shall be reduced by any payments made to
                  Employee under the Company's long-term disability policy. In
                  addition, Employee

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                  shall be entitled to receive any bonus earned by Employee
                  under Section 3(b) above through the date of termination of
                  employment payable at such time as any like bonuses are paid
                  by the Company generally.

         (c)      If Employee's employment is terminated either voluntarily or
                  involuntarily due to a "Change in Control" as defined by the
                  Securities and Exchange Commission, no payments shall be paid
                  under this Agreement. Employee shall be entitled to payments
                  agreed to in a separate letter agreement regarding "Change in
                  Control" dated August 9, 2000.

12.      Definition. For purposes of this Agreement, "Cause" means any of the
         following:

         (a)      Material breach of any of the terms of this Agreement or of
                  the Company's policies and procedures applicable to employees
                  and/or directors;

         (b)      Conviction of or plea of guilty or nolo contendere to a crime
                  involving moral turpitude or involving any violation of
                  securities or commodities law or regulation, or the issuance
                  of any court or administrative order enjoining or prohibiting
                  Employee from violating any such law or regulation;

         (c)      Repeated or habitual intoxication with alcohol or drugs while
                  on the premises of the Company or any of its affiliates or
                  during the performance by Employee of any of his duties
                  hereunder;

         (d)      Embezzlement of any property belonging or entrusted to the
                  Company or any of its affiliates;

         (e)      Repeated or protracted absence from work without cause;

         (f)      Willful misconduct or gross neglect of duties, or failure to
                  act with respect to duties or actions previously communicated
                  to Employee in writing by the Company Board;

13.      Integration; Amendment. This Agreement, the Change in Control Letter
         Agreement and the Option Agreement contain the entire agreement of the
         parties relating to the subject matter hereof and thereof, and together
         supersede and replace in their entirety any prior agreements or
         understandings concerning such subject matter. This Agreement may not
         be waived, changed, modified, extended, or discharged orally, but only
         by agreement in writing signed in the case of the Company by a duly
         authorized non-employee member of the Company Board.

14.      Arbitration. Any controversy, dispute, or claim arising out of or
         relating to Employee's employment or to this Agreement or breach
         thereof shall be settled by arbitration in accordance with the
         commercial rules of the American Arbitration Association at its
         Southfield, Michigan offices. Judgment upon any award may be entered in
         any circuit court or other court having jurisdiction thereof, without
         notice to the opposite party or parties. Anything contained herein to
         the contrary notwithstanding, this agreement to arbitrate shall not be
         deemed to be a waiver of the Company's right to secure equitable relief
         including injunction (whether as part of or separate from the
         arbitration proceeding) if and when otherwise appropriate.

15.      Applicable Law. This Agreement shall be governed by and construed in
         accordance with the laws of the State of Michigan applicable to
         contracts made and to be performed within such State.

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         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date first above written.

                                    NEWCOR, INC.

                                    BY:  /s/ James J. Connor
                                      -----------------------------------------

                                    Its:  President & Chief Executive Officer
                                        ---------------------------------------

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