<PAGE>

Exhibit 4(x)

                                                            December 19, 2001


James Connor
President and co-CEO
Newcor, Inc.
43252 Woodward Avenue, Suite 240
Bloomfield Hills, Michigan 48302

RE:      FINANCING ARRANGEMENTS AMONG COMERICA BANK ("BANK"), NEWCOR, INC.
         ("NEWCOR"), ROCHESTER GEAR, INC. ("ROCHESTER GEAR") (NEWCOR AND
         ROCHESTER GEAR ARE IDENTIFIED COLLECTIVELY AS "BORROWERS"), ENC CORP.,
         PLASTRONICS PLUS, INC., NEWCOR M-T-L, INC., GRAND MACHINING COMPANY,
         DECO TECHNOLOGIES, INC., DECO INTERNATIONAL, INC., TURN-MATIC, INC.
         (IDENTIFIED COLLECTIVELY, TOGETHER WITH NEWCOR, IN ITS CAPACITY AS A
         GUARANTOR OF CERTAIN OBLIGATIONS OF ROCHESTER GEAR, AND ROCHESTER GEAR,
         IN ITS CAPACITY AS A GUARANTOR OF THE OBLIGATIONS OF NEWCOR, AS
         "GUARANTORS")

Dear Mr. Connor:

Please refer to any and all documents, instruments and agreements executed in
connection with the financing arrangements from Bank to Borrower and Guarantors
(collectively, the "Loan Documents"). All amounts due from Borrower to Bank,
whether now or in the future, contingent, fixed, primary and/or secondary,
including, but not limited to, principal, interest, inside and outside counsel
fees, audit fees, costs, expenses and any and all other charges provided for in
the Loan Documents shall be known, in the aggregate, as the "Liabilities." All
capitalized terms not defined in this letter agreement ("Agreement") shall have
the meanings described in the Loan Documents.

As of December 6, 2001, the Liabilities include:

<TABLE>
<CAPTION>
LOANS (NOTE AMOUNT AND DATE)             PRINCIPAL                 INTEREST
----------------------------             ---------                 --------
<S>                                    <C>                        <C>
NEWCOR REVOLVING LOAN
($30,000,000; 3/28/01)                 $2,273,815.10              $31,709.14

NEWCOR TERM LOAN
($10,000,000; 5/13/96)                 $2,833,319.00              $15,772.60
                                       -------------              ----------

          TOTAL                        $5,107,134.10              $47,481.74
                                       =============              ==========

</TABLE>

The Liabilities also include: (a) Rochester Gear's obligations under a certain
Reimbursement Agreement with respect to a letter of credit issued by Bank at the
request of Rochester Gear in the amount of $6,170,191.78; and (b) Newcor's
obligations with respect to certain stand-by letters of credit issued by Bank at
Newcor's request in the aggregate amount of $700,000 (collectively, the "Letter
of Credit Obligations"). The amounts referenced above are exclusive of interest
accruing after December 6, 2001, costs and expenses (including, but not limited
to, inside and outside counsel fees).


<PAGE>

Newcor failed to pay the semi-annual interest payment under its 144A
subordinated notes due on September 4, 2001. The failure to cure this default
within the 30-day grace period constitutes a default under the Loan Documents.
In addition, Newcor is in default of certain financial covenants, as follows:
(a) Newcor's EBITDA as of September 30, 2001 was $5,124,000, which is less than
the EBITDA of $7,500,000 required under the Loan Documents; and (b) as of
September 30, 2001, Newcor and its Consolidated Subsidiaries had a ratio of
current assets to current liabilities of 0.30 to 1.00, which is below the ratio
of 1.25 to 1.00 required under the Loan Documents.

The Revolving Loan and the Term Loan are term obligations. As a result of and
for the reasons outlined above, Bank hereby accelerates the Revolving Loan and
the Term Loan and demands payment in full of all of the Liabilities. By copy of
this letter demand is also hereby made of the Guarantors of the Liabilities.

From and after the date of this letter, interest shall accrue on the Liabilities
at the highest rate provided for in the Loan Documents, which is: (a) Bank's
"Prime-based Rate" (as defined in the Loan Documents) plus three percent (3%),
with respect to the Revolving Loan; and (b) the greater of (i) 10.85% or (ii)
Bank's "Prime Rate" (as defined in the Loan Documents) plus three percent (3%),
with respect to the Term Loan. If this Agreement is properly and timely executed
and returned to Bank, then this paragraph shall be superseded by paragraph 7
below.

Bank may, in its sole discretion, consider requests for advances under the
Revolving Loan after the date of this letter and prior to acceptance of this
letter by Borrowers and Guarantors as provided below. Bank is not obligated to
make any such advances and if it elects to make certain advances is not
obligated to continue to make advances. Bank reserves all of its rights. Bank
will not consider advances which would increase the sum of the balance under the
Revolving Loan to more than $8,000,000.

Subject to timely, written acceptance by Borrowers and Guarantors of the
following conditions, Bank is willing to forbear until March 31, 2002, subject
to earlier termination as provided below, from further action to collect the
Liabilities:

1.       Borrowers and Guarantors acknowledge the Liabilities as set out in the
         Loan Documents, the amount of the Liabilities as stated above and the
         existence of the default. Borrowers and Guarantors further acknowledge
         that Bank's demand is timely and proper.

2.       Future administration of the Liabilities and the financing arrangements
         among Bank, Borrowers and Guarantors shall continue to be governed by
         the covenants, terms and conditions of the Loan Documents, which are
         incorporated by this reference, except to the extent that the Loan
         Documents have been superseded, amended, modified or supplemented by
         this Agreement or are inconsistent with this Agreement, then this
         Agreement shall govern. Any and all Loan Documents previously delivered
         to Bank are ratified and confirmed by Borrowers and Guarantors.

3.       Borrowers and Guarantors acknowledge Bank is under no obligation to
         advance funds or extend credit to Borrowers under the Loan Documents,
         or otherwise. Bank will not issue additional letters of credit.

4.       100% of the cash inflows of Newcor, Rochester Gear, Grand Machining
         Company, Deco Technologies, Inc. and Plastronics Plus, Inc. will be
         applied to the Revolving Loan. Subject to maintaining an advisory
         "Advance Formula" (defined below) equal to or greater than the balance
         owing on the Revolving Loan, and provided there are no further defaults
         under the terms of this Agreement, and no further defaults under the
         Loan Documents, Bank may, in its sole discretion, continue to advance
         to Newcor under the Revolving Loan, in accordance with the Loan
         Documents, through March 30, 2002. Effective immediately, the maximum
         amount available under the Revolving Loan (the "Revolver Cap") is
         $10,000,000. The Revolver Cap shall increase to $10,500,000 on January
         15, 2002. The Revolver Cap shall increase further to $13,500,000 on


<PAGE>

         February 15, 2002. The Advance Formula is equal to 70% (the "Advance
         Rate") of "Eligible Accounts" (as defined in the October 14, 1999
         Advance Formula Agreement). The Advance Rate shall further reduce by an
         additional 2% on each of January 15, 2002, February 15, 2002 and March
         15, 2002. In the event the balance on the Revolving Loan exceeds the
         Advance Formula at any time, no advances will be allowed. Effective
         immediately, advances under the Revolving Loan shall be at the
         Prime-based Rate only. Each borrowing request or Accounts Receivable
         collection must be accompanied by an accounts receivable report, in
         form satisfactory to Bank, with a minimum of one report per week.

5.       Borrowers and Guarantors acknowledge and agree they shall hold in
         express trust for Bank and immediately surrender in the form received
         all of their cash inflows to Bank by depositing such inflows into the
         following respective accounts maintained at Bank:



          BORROWER/GUARANTOR                                 ACCOUNT NO.

          Newcor, Inc.                                       1851-443406

          Newcor, Inc. (Newcor Bay City division)            1851-445310

          Newcor, Inc. (Machine Tool and Gear division)      1851-445286

          Newcor, Inc. (Deckerville division)                1851-445179

          Rochester Gear, Inc.                               1851-445294

          Grand Machining Company (d/b/a Deco Grand)         1851-445328

          Deco Technologies, Inc.                            1851-445302


         Notwithstanding the above requirement, Plastronics Plus, Inc., the
         Black Hawk division of Newcor, Inc. and the Walkerton division of
         Newcor, Inc. may each maintain a deposit account at a bank other than
         Bank, provided that each such depositor and each such depository bank
         execute and deliver a Blocked Account Control Agreement in form
         acceptable to Bank by no later than January 15, 2002.

6.       Notwithstanding Bank's demand of the Liabilities, interest on the
         Revolving Loan shall be due and payable on the first day of each and
         every month, effective as of the date of this Agreement. In addition,
         Newcor shall pay the principal installments on the Term Loan in the
         amount of $166,667, plus interest, on the tenth day of each month,
         effective as of the date of this Agreement.

7.       Effective as of the date of this Agreement, the non-default interest
         rate on the Revolving Loan shall be Bank's "Prime-based Rate" (as
         defined in the Loan Documents) plus one and one-half percent (1.5%),
         provided, however, that if Borrowers fail to furnish to Bank by March
         1, 2002 a commitment letter from a source of alternative financing for
         Borrowers satisfactory to Bank, then the non-default interest rate on
         the Revolving Loan shall be Bank's "Prime-based Rate" plus two and
         one-half percent (2.5%) effective as of March 1, 2002. Effective as of
         the date of this Agreement, the non-default interest rate on the Term
         Loan shall be 8.35%, provided, however, that if Borrowers fail to
         furnish to Bank by March 1, 2002 a commitment letter from a source of
         alternative financing for Borrowers satisfactory to Bank, then the
         non-default interest rate on the Term Loan shall be 9.35% effective as
         of March 1, 2002. Upon the occurrence of a default under


<PAGE>

         the terms of this Agreement or any further defaults under the Loan
         Documents, then the Liabilities shall accrue interest at the rate
         otherwise provided in this paragraph plus three percent (3%).

8.       Borrowers and Guarantors shall furnish to Bank by no later than January
         31, 2002 appraisals by an appraiser acceptable to Bank on all machinery
         and equipment of Borrowers or Guarantors at the following facilities:
         Blackhawk Engineering, Newcor Technologies, Deckerville, Walkerton,
         Newcor Bay City and Plastronics).

9.       On or before December 21, 2001, Newcor shall deliver to Bank
         concurrently with execution of this Agreement the legal descriptions
         for the real property at each of Newcor's six facilities. Newcor shall
         furnish to Bank by no later than January 15, 2002 executed mortgages on
         such facilities, in form satisfactory to Bank, which mortgages shall
         secure all of the Liabilities. On or before January 15, 2002 Borrowers
         and Guarantors shall deliver to Bank lessor's acknowledgement and
         subordination agreements, in form and substance satisfactory to Bank,
         with respect to each of their respective leaseholds, duly executed by
         their respective landlords.

10.      Borrowers agree to use their best efforts to procure alternative
         financing to repay the Liabilities in full and replace the Letters of
         Credit by the expiration of this Agreement. Borrowers shall provide to
         Bank, upon Bank's request, written evidence of these efforts. Borrowers
         shall provide to Bank as and when received by Borrowers copies of any
         proposals or commitment letters. In addition, Borrowers shall provide
         to Bank by March 1, 2002 a commitment letter from a source of
         alternative financing for Borrowers, which commitment letter shall be
         satisfactory to Bank in its sole discretion.

11.      By no later than March 1, 2002, Newcor shall enter into a definitive
         agreement for the restructuring of the 144A subordinated debt in form
         and substance satisfactory to Bank in Bank's sole discretion.

12.      Borrowers shall pay to Bank a fee of $25,000. The fee is in
         consideration of Bank's costs in negotiating and structuring this
         Agreement (and not as consideration for any specific period of
         forbearance provided for herein). The fee is fully earned upon
         acceptance of this Agreement by Borrowers and Guarantors and is not
         refundable. The fee is due and payable concurrently with execution of
         this Agreement and may be charged to Newcor's checking account
         maintained at Bank.

13.      Newcor agrees that it will not make any further payments to the Trustee
         for the holders of the 144A subordinated notes.

14.      Concurrently with execution of this Agreement, the applicable Borrowers
         and Guarantors shall execute and deliver to Bank the following
         additional documents, in the form attached:

         (a) Amended and Restated Guaranties (Grand Machining Company, Deco
                  Technologies, Inc., Deco International, Inc., Turn-Matic,
                  Inc., Plastronics Plus, Inc., ENC Corp., Newcor M-T-L, Inc.
                  and Rochester Gear);

         (b) Security Agreements (All Assets) (Newcor, Grand Machining Company,
                  Deco Technologies, Inc., Deco International, Inc., Turn-Matic,
                  Inc., Plastronics Plus, Inc., ENC Corp., Newcor M-T-L, Inc.
                  and Rochester Gear);

         (c) Authority to Procure Loans (Resolutions of Corporate Board and
                  Incumbency Certification) for Newcor; and



<PAGE>

         (d) Authority to Support Another's Borrowings (Resolutions of Corporate
                  Board and Incumbency Certification) for Rochester Gear, ENC
                  Corp., Plastronics Plus, Inc., Newcor M-T-L, Inc., Grand
                  Machining Company, Deco Technologies, Inc., Deco
                  International, Inc. and Turn-Matic, Inc.

         In addition, Borrowers and Guarantors shall also deliver to Bank
         concurrently with execution of this Agreement a copy of their
         respective by-laws.

15.      It shall be a default under this Agreement if the Trustee or the
         holders of the 144A subordinated notes exercise any remedies with
         respect to such notes, including but not limited to acceleration of the
         subordinated debt, commencement of suit or commencement of an
         involuntary bankruptcy proceeding against Newcor.

16.      Bank agrees that, for the purpose of this forbearance agreement, a
         default under the EBITDA and Current Ratio financial covenants in the
         Loan Documents for the quarter ending December 31, 2001 will not be
         deemed to be a default under this Agreement or a further default under
         the Loan Documents, provided that EBITDA is not less than $4,000,000
         and the Current Ratio is not less than .20 to 1.

17.      Borrowers and Guarantors acknowledge and agree the Loan Documents
         presently provide for and they shall reimburse Bank for any and all
         costs and expenses of Bank, including, but not limited to, all inside
         and outside counsel fees of Bank whether in relation to drafting,
         negotiating or enforcement or defense of the Loan Documents or this
         Agreement, including any preference or disgorgement actions as defined
         in this Agreement and all of Bank's audit fees, incurred by Bank in
         connection with the Liabilities, Bank's administration of the
         Liabilities and/or any efforts of Bank to collect or satisfy all or any
         part of the Liabilities. Borrowers and Guarantors shall immediately
         reimburse Bank for all of Bank's costs and expenses upon Bank's
         incurrence thereof or upon demand.

18.      Loan payments, interest on the Liabilities, loan administration
         expenses, including, but not limited to, all inside and outside counsel
         fees of Bank and Bank's audit fees, may be charged directly to Newcor's
         checking account maintained with Bank.

19.      Borrowers and Guarantors will maintain all commercial accounts with
         Bank, except as otherwise permitted under paragraph 5 above.

20.      In addition to all reporting currently required by the Loan Documents:
         (a) Borrowers and Guarantors shall provide Bank a summary of Borrowers'
         and Guarantors' accounts payable and accounts receivable as of the last
         day of each week showing which accounts payable and accounts receivable
         are up to 30, 31 to 60, 61 to 90, and 91 days or more past the invoice
         date and listing the names and addresses of creditors and account
         debtors, as applicable. These summaries are due on Friday of the
         following week. (b) Borrowers shall provide Bank with a comparison of
         actual results to projections as of the last day of each month. These
         reports are due by the 25th of the following month. (c) Borrowers shall
         provide Bank with a written report on the status of Borrowers'
         refinancing efforts and its negotiations with the 144A subordinated
         noteholders on the 10th day of each month (or more frequently if Bank
         so requests). (d) Borrowers shall provide Bank any other reporting
         requested.


<PAGE>

21.      Borrowers and Guarantors acknowledge and agree the Loan Documents
         presently provide and they shall permit Bank to conduct such fair
         market value appraisals, inspections, surveys and/or testing, whether
         for environmental contamination or otherwise, that Bank deems
         necessary, on any and all real property upon which Bank may possess a
         mortgage securing the Liabilities, and the cost of such appraisals,
         inspections, surveys and testing are part of the costs and expenses for
         which the Borrowers and Guarantors must reimburse Bank.

22.      To the extent any payment received by Bank is deemed a preference,
         fraudulent transfer or otherwise by a court of competent jurisdiction
         which requires the Bank to disgorge such payment then, such payment
         will be deemed to have never occurred and the Liabilities will be
         adjusted accordingly.

23.      This Agreement shall be governed and controlled in all respects by the
         laws of the State of Michigan, without reference to its conflict of law
         provisions, including interpretation, enforceability, validity and
         construction.

24.      Bank expressly reserves the right to exercise any or all rights and
         remedies provided under the Loan Documents and applicable law except as
         modified herein. Bank's failure to immediately exercise such rights and
         remedies shall not be construed as a waiver or modification of those
         rights or an offer of forbearance.

25.      This Agreement will inure to the benefit of Bank and all its past,
         present and future parents, subsidiaries, affiliates, predecessors and
         successor corporations and all of their subsidiaries and affiliates.

26.      Borrowers and Guarantors agree to execute any and all additional or
         supplemental documentation, and provide such further assistance and
         assurances as Bank may require, in Bank's sole and absolute discretion,
         to give full effect of the terms, conditions and intentions of this
         Agreement.

27.      This Agreement may be executed in counterparts and facsimiles and the
         counterparts, when properly executed and delivered by the signing
         deadline, will constitute a fully executed complete agreement.

28.      Bank anticipates that discussions addressing the Liabilities may take
         place in the future. During the course of such discussions, Bank,
         Borrower and Guarantors may touch upon and possibly reach a preliminary
         understanding on one or more issues prior to concluding negotiations.
         Notwithstanding this fact and absent an express written waiver by Bank,
         Bank will not be bound by an agreement on any individual issues unless
         and until an agreement is reached on all issues and such agreement is
         reduced to writing and signed by Borrowers and Guarantors, and Bank.

29.      As of the date of this Agreement, there are no offers outstanding from
         Bank to Borrowers and Guarantors. Any prior offer by Bank, whether oral
         or written is hereby rescinded in full. There are no oral agreements
         between Bank and Borrowers and Guarantors; any agreements concerning
         the Liabilities are expressed only in the existing Loan Documents. The
         duties and obligations of Borrowers and Guarantors and Bank shall be
         only as set forth in the Loan Documents and this Agreement when
         executed by all parties.

30.      Borrowers and Guarantors acknowledge that they have reviewed (or have
         had the opportunity to review) this Agreement with counsel of their
         choice and have executed this Agreement of their own free will and
         accord and without duress or coercion of any kind by Bank or any other
         person or entity.


<PAGE>

31.      BORROWERS, GUARANTORS AND BANK ACKNOWLEDGE AND AGREE THAT THE RIGHT TO
         TRIAL BY JURY IS A CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED. EACH
         PARTY, AFTER CONSULTING (OR HAVING HAD THE OPPORTUNITY TO CONSULT) WITH
         COUNSEL OF THEIR CHOICE, KNOWINGLY AND VOLUNTARILY, AND FOR THEIR
         MUTUAL BENEFIT WAIVES ANY RIGHT TO TRIAL BY JURY IN THE EVENT OF
         LITIGATION REGARDING THE PERFORMANCE OR ENFORCEMENT OF, OR IN ANY WAY
         RELATED TO, THIS AGREEMENT, THE LOAN DOCUMENTS OR THE LIABILITIES.

32.      BORROWERS AND GUARANTORS, IN EVERY CAPACITY, INCLUDING, BUT NOT LIMITED
         TO, AS SHAREHOLDERS, PARTNERS, OFFICERS, DIRECTORS, INVESTORS AND/OR
         CREDITORS OF BORROWERS AND/OR GUARANTORS, OR ANY ONE OR MORE OF THEM,
         HEREBY WAIVE, DISCHARGE AND FOREVER RELEASE BANK, BANK'S EMPLOYEES,
         OFFICERS, DIRECTORS, ATTORNEYS, STOCKHOLDERS AND SUCCESSORS AND
         ASSIGNS, FROM AND OF ANY AND ALL CLAIMS, CAUSES OF ACTION, DEFENSES,
         COUNTERCLAIMS OR OFFSETS AND/OR ALLEGATIONS BORROWERS AND/OR GUARANTORS
         MAY HAVE OR MAY HAVE MADE OR WHICH ARE BASED ON FACTS OR CIRCUMSTANCES
         ARISING AT ANY TIME UP THROUGH AND INCLUDING THE DATE OF THIS
         AGREEMENT, WHETHER KNOWN OR UNKNOWN, AGAINST ANY OR ALL OF BANK, BANK'S
         EMPLOYEES, OFFICERS, DIRECTORS, ATTORNEYS, STOCKHOLDERS AND SUCCESSORS
         AND ASSIGNS.

33.      Borrowers and Guarantors shall properly execute this Agreement and hand
         deliver same to the undersigned by no later than 5:00 p.m. on January
         4, 2002.

Bank reserves the right to terminate its forbearance prior to March 31, 2002, in
the event of any new defaults under the Loan Documents, defaults under this
Agreement, in the event of further deterioration in the financial condition of
Borrowers or Guarantors or further deterioration in Bank's collateral position,
and/or in the event Bank, for any reason, believes that the prospect of payment
or performance is impaired.

Very truly yours,


/s/ Preeti S. Sarnaik
---------------------

Preeti S. Sarnaik
Assistant Vice President
P.O. Box 75000
Detroit, Michigan 48275-3240
(313) 222-5185
fax:   222-3503



<PAGE>


ACKNOWLEDGED AND AGREED:


NEWCOR, INC.
(AS A BORROWER AND IN ITS CAPACITY AS GUARANTOR
OF CERTAIN OBLIGATIONS OF ROCHESTER GEAR, INC.)


By:       /s/ James J. Connor                     Date:    12/21/01
       -----------------------------

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


ROCHESTER GEAR, INC.
(AS A BORROWER AND IN ITS CAPACITY AS
GUARANTOR OF NEWCOR, INC.'S OBLIGATIONS)


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


ENC CORP.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


PLASTRONICS PLUS, INC.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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



<PAGE>


NEWCOR M-T-L, INC.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


GRAND MACHINING COMPANY


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


DECO TECHNOLOGIES, INC.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


DECO INTERNATIONAL, INC.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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


TURN-MATIC, INC.


By:       /s/ James J. Connor                     Date:   12/21/01
       -----------------------------

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