<PAGE>   1
                                                                     EXHIBIT 4
                           SECOND AMENDMENT AGREEMENT

         This Second Amendment Agreement is made as of the 1st day of November,
1999, among PARK-OHIO INDUSTRIES, INC., an Ohio corporation ("Borrower"), the
banking institutions listed on SCHEDULE 1 to the Credit Agreement, as
hereinafter defined ("Banks"), KEYBANK NATIONAL ASSOCIATION, as administrative
agent for the Banks ("Administrative Agent"), and THE HUNTINGTON NATIONAL BANK,
as co-agent for the Banks ("Co-Agent" and, together with Administrative Agent,
"Agents").

         WHEREAS, Borrower, Agents and the Banks are parties to a certain
Amended and Restated Credit Agreement dated as of November 2, 1998, as amended
and as it may from time to time be further amended, restated or otherwise
modified, which provides, among other things, for loans aggregating One Hundred
Fifty Million Dollars ($150,000,000), all upon certain terms and conditions (the
"Credit Agreement");

         WHEREAS, Borrower, Agents and the Banks desire to amend the Credit
Agreement to provide for an additional revolving credit tranche thereunder and
to modify certain other provisions thereof; and

         WHEREAS, each term used herein shall be defined in accordance with the
Credit Agreement:

         NOW, THEREFORE, in consideration of the premises and mutual covenants
contained herein and for other valuable considerations, Borrower, Agents and the
Banks agree as follows:

         1. Article I of the Credit Agreement is hereby amended to delete the
definitions of "Advantage", "Applicable Margin", "Commitment", "Commitment
Percentage", "Commitment Period", "Indenture", "Loan", "Note", "Senior
Subordinated Note", "Senior Subordinated Noteholders", "Total Commitment Amount"
and "Total Senior Funded Indebtedness" therefrom and
to insert in place thereof the following:

                  "Advantage" shall mean any payment (whether made voluntarily
         or involuntarily, by offset of any deposit or other indebtedness or
         otherwise) received by any Bank in respect of the Debt, if such payment
         results in that Bank having less than its Pro Rata Share of the
         Applicable Debt then outstanding, than was the case immediately before
         such payment.

                  "Applicable Margin" shall mean, with respect to any Loan, the
         number of basis points (depending upon whether such Loan is a Prime
         Rate Loan or a LIBOR Loan) set forth in the following matrix:


<PAGE>   2


<TABLE>
<CAPTION>
                                                          APPLICABLE BASIS             APPLICABLE BASIS
        TYPE OF LOAN                                      POINTS FOR LIBOR             POINTS FOR PRIME
                                                                LOANS                     RATE LOANS
--------------------------------------------------------------------------------------------------------
<S>                                                       <C>                          <C>
Tranche A Loan                                             90 basis points             -100 basis points
--------------------------------------------------------------------------------------------------------
Tranche B Loan                                            150 basis points             -50 basis points
--------------------------------------------------------------------------------------------------------
Tranche C Loan (at any time that there                    170 basis points             -30 basis points
is no Tranche D Loan outstanding)
--------------------------------------------------------------------------------------------------------
Tranche C Loan (at any time that there                    185 basis points             -15 basis points
is a Tranche D Loan outstanding)
--------------------------------------------------------------------------------------------------------
Tranche D Loan                                            220 basis points              20 basis points
</TABLE>

         Each change in the Applicable Margin with respect to any Tranche C Loan
         shall be effective immediately. The above matrix does not modify or
         waive, in any respect, the requirements of Section 5.7 hereof, the
         rights of the Banks to charge the Default Rate, or the rights and
         remedies of Agents and the Banks pursuant to Articles VII and VIII
         hereof.

                  "Commitment" shall mean the obligation hereunder of the Banks,
         during the applicable Commitment Period, to make Loans pursuant to the
         Tranche A Commitments, the Tranche B Commitments, the Tranche C
         Commitments and the Tranche D Commitments, up to the Total Commitment
         Amount.

                  "Commitment Percentage" shall mean Applicable Commitment
         Percentage.

                  "Commitment Period" shall mean (a) with respect to the Tranche
         A Commitments, the Tranche B Commitments and the Tranche C Commitments,
         the period from the Closing Date to April 30, 2001, and (b) with
         respect to the Tranche D Commitments, the period from the Tranche D
         Closing Date to April 30, 2001; or such earlier date on which the
         Commitment shall have been terminated pursuant to Article VIII hereof.

                  "Indenture" shall mean both of the following and any thereof
         (a) the 1997 Indenture and (b) the 1999 Indenture; as either of the
         foregoing may, with the prior written consent of Administrative Agent
         and the Majority Banks, be from time to time amended, restated or
         otherwise modified or replaced.

                  "Loan" shall mean the credit extended to Borrower by the Banks
         in accordance with Section 2.1A, B, C or D hereof.

                  "Note" shall mean any Tranche A Note, Tranche B Note, Tranche
         C Note, Tranche D Note or other note delivered pursuant to this
         Agreement.

                  "Senior Subordinated Noteholder" shall mean any one of the
         Senior Subordinated Noteholders under any Indenture.

<PAGE>   3

                  "Senior Subordinated Notes" shall mean the Senior Subordinated
         Notes issued pursuant to any Indenture.

                  "Total Commitment Amount" shall mean the principal amount of
         One Hundred Seventy-Five Million Dollars ($175,000,000) (or such lesser
         amount as shall be determined pursuant to Section 2.5 hereof).

                  "Total Senior Funded Indebtedness" shall mean, on a
         Consolidated basis and in accordance with GAAP, (a) Total Funded
         Indebtedness minus (b) all Subordinated Indebtedness.

         2. Article I of the Credit Agreement is hereby amended to add the
following new definitions thereto:

                  "Applicable Commitment Percentage" shall mean, for each Bank,
         (a) with respect to the Tranche A Commitments, the Tranche B
         Commitments and the Tranche C Commitments, the percentage set forth
         opposite such Bank's name under the column headed "Tranche A through
         Tranche C Commitment Percentage" as described in SCHEDULE 1 hereof; and
         (b) with respect to the Tranche D Commitments, the percentage set forth
         opposite such Bank's name under the column headed "Tranche D Commitment
         Percentage" as described in SCHEDULE 1 hereof.

                  "Applicable Debt" shall mean (a) with respect to the Tranche A
         Commitments, the Tranche B Commitments and the Tranche C Commitments,
         collectively, (i) all Indebtedness incurred by Borrower to Agents or
         the Banks pursuant to this Agreement (other than pursuant to the
         Tranche D Commitments) and includes the principal of and interest on
         all Notes (other than the Tranche D Notes), (ii) each extension,
         renewal or refinancing thereof in whole or in part, and (iii) the
         commitment fees, other fees and any prepayment fees payable hereunder
         (other than the commitment fees and any prepayment fees payable in
         connection with the Tranche D Commitments); and (b) with respect to the
         Tranche D Commitments, collectively, (i) all Indebtedness incurred by
         Borrower to Agents or the Banks pursuant to the Tranche D Commitments
         and includes the principal of and interest on the Tranche D Notes, (ii)
         each extension, renewal or refinancing thereof in whole or in part, and
         (iii) the commitment fees and any prepayment fees payable in connection
         with the Tranche D Commitments.

                  "Fixed Charge Coverage Ratio Condition" shall mean any time
         that (a) Borrower's Consolidated Fixed Charge Coverage Ratio (as
         defined in the Indenture) is less than 2.25 to 1.00, as calculated in
         accordance with the terms and conditions of the Indenture, or (b) any
         Subsidiary's Consolidated Fixed Charge Coverage Ratio (as defined in
         the Indenture) is less than 2.50 to 1.00, as calculated in accordance
         with the terms and conditions of the Indenture.

                  "1997 Indenture" shall mean that certain Indenture dated as of
         November 25, 1997, between Borrower and Norwest Bank Minnesota,
         National Association, as trustee, pursuant to which the Senior
         Subordinated Notes were issued to the Senior Subordinated Noteholders,

<PAGE>   4

         as the same may, with the prior written consent of Administrative Agent
         and the Majority Banks, be from time to time amended, restated or
         otherwise modified or replaced.

                  "1999 Indenture" shall mean that certain Indenture dated as of
         June 2, 1999, between Borrower and Norwest Bank Minnesota, National
         Association, as trustee, pursuant to which the Senior Subordinated
         Notes were issued to the Senior Subordinated Noteholders, as the same
         may, with the prior written consent of Administrative Agent and the
         Majority Banks, be from time to time amended, restated or otherwise
         modified or replaced.

                  "Pro Rata Basis" or "pro rata basis" shall mean distribution
         to the Banks by Administrative Agent in accordance with the Applicable
         Commitment Percentages.

                  "Pro Rata Share" or "pro rata share" shall mean, with respect
         to the Applicable Debt, a Bank's share in accordance with such Bank's
         Applicable Commitment Percentage.

                  "Ratable Account" or "ratable account" shall mean each Bank's
         share of the Applicable Debt in accordance with such Bank's Applicable
         Commitment Percentage.

                  "Ratable Share" or "ratable share" shall mean each Bank's
         share of the Applicable Debt in accordance with such Bank's Applicable
         Commitment Percentage.

                  "Ratably" or "ratably" shall mean in accordance with each
Bank's Ratable Share.

                  "Tranche D Bank" shall mean any Bank with a Tranche D
Commitment.

                  "Tranche D Closing Date" shall mean November 1, 1999.

                  "Tranche D Commitments" shall mean the obligation hereunder of
         each Tranche D Bank to make Tranche D Loans, during the applicable
         Commitment Period, up to the amount set forth opposite such Tranche D
         Bank's name under the column headed "Tranche D Commitment Amount" as
         set forth on SCHEDULE 1 hereof (or such lesser amount as shall be
         determined pursuant to Section 2.5 hereof); provided that the aggregate
         amount of the Tranche D Commitments shall not exceed Twenty-Five
         Million Dollars ($25,000,000).

                  "Tranche D Conditions" shall include the following: (a) any
         payment of principal under this Agreement shall be applied first to the
         principal then outstanding on the Tranche D Commitments; (b) any
         payment of interest under this Agreement shall be applied first to the
         interest then outstanding on the Tranche D Commitments; and (c) any
         payment of commitment fees or other fees owing under this Agreement
         shall be applied first to the commitment and other fees then owing with
         respect to the Tranche D Commitments.

                  "Tranche D Leverage Ratio Condition" shall mean any time that
         a Tranche D Loan is outstanding.

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<PAGE>   5

                  "Tranche D Loan" shall mean a Loan granted to Borrower by the
         Tranche D Banks in accordance with Section 2.1D hereof.

                  "Tranche D Note" shall mean the Tranche D Note executed and
         delivered pursuant to Section 2.1D hereof.

         3. Section 2.1 of the Credit Agreement is hereby amended to delete the
second and third paragraphs therefrom and to insert in place thereof the
following:

                  Each Bank, for itself and not one for any other, agrees to
         participate in Loans made hereunder during the Commitment Period on
         such basis that (a) immediately after the completion of any borrowing
         by Borrower, the aggregate principal amount then outstanding on the
         Notes issued to such Bank shall not be in excess of the Maximum Amount
         for such Bank, and (b) such aggregate principal amounts outstanding on
         the Tranche A Note, the Tranche B Note and the Tranche C Note,
         respectively, issued to such Bank shall represent that percentage of
         the aggregate principal amount then outstanding on all Tranche A Notes,
         Tranche B Notes and Tranche C Notes (including all such Notes held by
         such Bank), respectively, which is such Bank's Applicable Commitment
         Percentage; and (c) such aggregate principal amount outstanding on the
         Tranche D Note issued to such Bank shall represent that percentage of
         the aggregate principal amount then outstanding on all Tranche D Notes
         (including the Tranche D Note held by such Bank) which is such Bank's
         Applicable Commitment Percentage.

                  Each borrowing from the Banks hereunder shall be made pro rata
         according to the Banks' respective Applicable Commitment Percentages.
         The Loans may be made as Tranche A Loans, Tranche B Loans, Tranche C
         Loans and Tranche D Loans as follows:

         4. Section 2.1 of the Credit Agreement is hereby amended to add the
following new subsection D thereto:

                  D. Tranche D Loans. Subject to the terms and conditions of
         this Agreement, during the applicable Commitment Period, the Tranche D
         Banks shall make a Tranche D Loan or Tranche D Loans to Borrower in
         such amount or amounts as Borrower may from time to time request, but
         not exceeding in aggregate principal amount at any time outstanding
         hereunder the aggregate amount of the Tranche D Commitments; provided,
         however, that Borrower shall not request any Tranche D Loan hereunder
         unless the Tranche A Commitments, Tranche B Commitments and Tranche C
         Commitments have been fully funded. Borrower shall have the option,
         subject to the terms and conditions set forth herein, to borrow Tranche
         D Loans, maturing on the last day of the Commitment Period, by means of
         any combination of (a) Prime Rate Loans, or (b) LIBOR Loans.

                  Borrower shall pay interest, for the benefit of the Tranche D
         Banks, on the unpaid principal amount of Prime Rate Loans outstanding
         from time to time from the date thereof until paid at the Derived Prime
         Rate from time to time in effect. Interest on such Prime Rate

                                       5

<PAGE>   6

         Loans shall be payable, commencing December 31, 1999, and on the last
         day of each succeeding March, June, September and December of each year
         and at the maturity thereof.

                  Borrower shall pay interest, for the benefit of the Tranche D
         Banks, on the unpaid principal amount of each LIBOR Loan outstanding
         from time to time, from the date thereof until paid, at the Derived
         LIBOR Rate, fixed in advance for each Interest Period as herein
         provided for each such Interest Period. Interest on such LIBOR Loans
         shall be payable on each Interest Adjustment Date with respect to an
         Interest Period (provided that if an Interest Period exceeds three (3)
         months, the interest must be paid every three (3) months, commencing
         three (3) months from the beginning of such Interest Period).

                  The obligation of Borrower to repay the Prime Rate Loans and
         the LIBOR Loans made by each Tranche D Bank and to pay interest thereon
         shall be evidenced by a Tranche D Note of Borrower in the form of
         EXHIBIT F hereto, dated as of the Tranche D Closing Date, and payable
         to the order of such Tranche D Bank in the principal amount of its
         Tranche D Commitment, or, if less, the aggregate unpaid principal
         amount of Tranche D Loans made hereunder by such Bank. Subject to the
         provisions of this Agreement, Borrower shall be entitled under this
         Section 2.1D to borrow funds, repay the same in whole or in part and
         re- borrow hereunder at any time and from time to time during the
         applicable Commitment Period.

         5. The Credit Agreement is hereby amended to delete Section 2.3
therefrom and to insert in place thereof the following:

                  SECTION 2.3. PAYMENT ON NOTES, ETC. Each payment made on Loans
         hereunder shall be applied first to Tranche D Loans, if any are
         outstanding, then to Tranche C Loans, if any are outstanding, then to
         Tranche B Loans, if any are outstanding, and then to Tranche A Loans.
         All payments of principal, interest and commitment and other fees shall
         be made to Administrative Agent in immediately available funds for the
         account of the Banks on a Pro Rata Basis (except as to payments made
         exclusively for the benefit of Administrative Agent pursuant to the
         Agent Fee Letter), and Administrative Agent, within one (1) Business
         Day, shall distribute to each Bank, in accordance with the Tranche D
         Conditions, its Ratable Share of the amount of principal, interest, and
         commitment and other fees received by it for the account of such Bank.
         Whenever payments are made to Administrative Agent "for the benefit of
         the Banks", "for the benefit of the Banks" shall mean on a Pro Rata
         Basis. Each Bank shall record (a) any principal, interest or other
         payment, and (b) the principal amount of the Prime Rate Loans and the
         LIBOR Loans and all prepayments thereof and the applicable dates with
         respect thereto, by such method as such Bank may generally employ;
         provided, however, that failure to make any such entry shall in no way
         detract from Borrower's obligations under each such Note. The aggregate
         unpaid amount of Loans set forth on the records of Administrative Agent
         shall be rebuttably presumptive evidence of the principal and interest
         owing and unpaid on each Note. Whenever any payment to be made
         hereunder, including, without limitation, any payment to be made on any
         Note, shall be stated to be due on a day that is not a Business Day,
         such

                                       6

<PAGE>   7

         payment shall be made on the next succeeding Business Day and such
         extension of time shall in each case be included in the computation of
         the interest payable on such Note; provided, however, that with respect
         to any LIBOR Loan, if the next succeeding Business Day falls in the
         succeeding calendar month, such payment shall be made on the preceding
         Business Day and the relevant Interest Period shall be adjusted
         accordingly.

         6. Section 2.4 of the Credit Agreement is hereby amended to delete the
first paragraph therefrom and to insert in place thereof the following:

                  SECTION 2.4. PREPAYMENT. Borrower shall have the right at any
         time or from time to time to prepay, on a Pro Rata Basis for all of the
         Banks, all or any part of the principal amount of the Notes then
         outstanding as designated by Borrower, plus interest accrued on the
         amount so prepaid to the date of such prepayment, subject, however, to
         the Tranche D Conditions. Borrower shall give Administrative Agent
         notice of prepayment of any Prime Rate Loan by not later than 11:00
         A.M. (Cleveland, Ohio time) on the Business Day such prepayment is to
         be made and written notice of the prepayment of any LIBOR Loan not
         later than 1:00 P.M. (Cleveland, Ohio time) three (3) Business Days
         before the Business Day on which such prepayment is to be made.
         Prepayments of Prime Rate Loans shall be without any premium or
         penalty.

         7. Section 2.5 of the Credit Agreement is hereby amended to delete
subsection (e) therefrom and to insert in place thereof the following:

                  (e) Borrower may at any time or from time to time permanently
         reduce in whole or in part the Commitment of the Banks hereunder to an
         amount not less than the aggregate principal amount of the Loans then
         outstanding, by giving Agents not fewer than five (5) Business Days'
         notice, provided that (i) any partial reduction shall be applied, on a
         Pro Rata Basis for all of the Banks, first to the Tranche D
         Commitments, then to the Tranche C Commitments, then to the Tranche B
         Commitments and, finally, to the Tranche A Commitments, and (ii) any
         partial reduction shall be in an aggregate amount of Five Million
         Dollars ($5,000,000) or any multiple thereof. Administrative Agent
         shall promptly notify each Bank of the date of each such reduction and
         such Bank's proportionate share thereof. After each such reduction, the
         commitment fees payable hereunder shall be calculated upon the
         Commitment of the Banks as so reduced. If Borrower reduces in whole the
         Commitment of the Banks, on the effective date of such reduction
         (Borrower having prepaid in full the unpaid principal balance, if any,
         of the Notes, together with all interest and commitment and other fees
         accrued and unpaid), all of the Notes shall be delivered to
         Administrative Agent marked "Canceled" and Administrative Agent shall
         redeliver such Notes to Borrower. Any partial reduction in the
         Commitment of the Banks shall be effective during the remainder of the
         Commitment Period.

         8. Section 2.5 of the Credit Agreement is hereby amended to add new a
subsection (f) thereto as follows:


                                        7

<PAGE>   8

                  (f) Borrower shall pay to Administrative Agent, for the
         account of the Tranche D Banks, as a consideration for the Tranche D
         Commitments, a commitment fee from the Tranche D Closing Date to and
         including the last day of the Commitment Period equal to (i) one-half
         percent (1/2%) per annum, times (ii) the average daily unborrowed
         amount of the Tranche D Commitments. The commitment fee shall be
         payable, in arrears, on December 31, 1999 and on the last day of each
         March, June, September and December thereafter, and on the last day of
         the Commitment Period.

         9. The Credit Agreement is hereby amended to add a new Section 2.9
thereto as follows:

                  SECTION 2.9. FIXED CHARGE COVERAGE RATIO CONDITION. Borrower
         shall provide immediate written notice to Agents and the Banks at any
         time that the Fixed Charge Coverage Ratio Condition exists or, within
         the next three (3) months, is likely to exist, and, so long as the
         Fixed Charge Coverage Ratio exists, Borrower shall not request any
         Loan, and the Banks shall not be obligated to make any Loan, unless (a)
         the proceeds of such Loan shall constitute Permitted Indebtedness (as
         defined in the Indenture), and (b) upon request of Administrative
         Agent, Borrower shall provide to the Banks such evidence of use of
         proceeds of the Loans and such opinion of counsel with respect to the
         Indenture, as Administrative Agent may require in its reasonable
         discretion.

         10. Section 5.7 of the Credit Agreement is hereby amended to delete
subsection (c) therefrom and to insert in place thereof the following:

                  (c) LEVERAGE RATIO. Borrower shall not suffer or permit at any
         time the Leverage Ratio to exceed (i) 5.00 to 1.00 for the period from
         the Closing Date through December 30, 1999 at any time that the
         Leverage Ratio Condition exists during such period, (ii) on December
         31, 1999 through June 29, 2000, 5.00 to 1.00 or, in the event that the
         Tranche D Leverage Ratio Condition exists, 4.50 to 1.00, and (iii) on
         June 30, 2000 and thereafter, 5.00 to 1.00 or, in the event that the
         Tranche D Leverage Ratio Conditions exists, 4.00 to 1.00.

         11. The Credit Agreement is hereby amended to delete Section 6.18
therefrom and to insert in place thereof the following:

                  SECTION 6.18. INDENTURE. (a) No Event of Default (as defined
         in the Indenture) or Default (as defined in the Indenture) exists, nor
         will any such Event of Default or Default exist immediately after the
         granting of any Loan, under the Indenture, the Senior Subordinated
         Notes or any agreement executed by Borrower in connection therewith;
         (b) no Company has incurred (as defined in the Indenture) any
         Designated Senior Indebtedness (as defined in the Indenture) other than
         the Debt; and (c) no Company has "incurred" (as defined in the
         Indenture) either prior to or after the granting of any Loan, any
         Indebtedness

                                       8

<PAGE>   9

         (as defined in the Indenture) in violation of Section 4.06 (Limitation
         on Additional Indebtedness) of the Indenture.

         12. The Credit Agreement is hereby amended to delete Section 6.19
therefrom and to insert in place thereof the following:

                  SECTION 6.19. REVOLVING CREDIT FACILITY. This Agreement (a)
         constitutes "Revolving Credit Facility" (as defined in the 1999
         Indenture), and (b) is a replacement of the Credit Agreement dated as
         of April 11, 1995, as amended, among Borrower, KeyBank National
         Association (successor by merger to Society National Bank), as Agent,
         and the banking institutions listed on Annex 1 attached thereto, and
         the Credit Agreement dated as of January 14, 1998 among Borrower,
         KeyBank National Association, as Administrative Agent, The Huntington
         National Bank, as Co-Agent, and the banking institutions listed on
         Schedule 1 attached thereto.

         13. The Credit Agreement is hereby amended to delete Section 7.10
therefrom and to insert in place thereof the following:

                  SECTION 7.10. INDENTURE. If (a) any Event of Default (as
         defined in the Indenture), or any event or condition that with the
         lapse of time or giving of notice or both would constitute an Event of
         Default (as defined in the Indenture), shall exist under the Indenture,
         the Senior Subordinated Notes or any agreement executed by Borrower in
         connection therewith, (b) without the prior written consent of Agents
         and the Majority Banks, the Indenture or the Senior Subordinated Notes
         shall be amended or modified in any respect or replaced, or (c) the
         Senior Subordinated Notes shall be accelerated for any reason.


         14. The Credit Agreement is hereby amended to delete Section 8.4
therefrom and to insert in place thereof the following:

                  SECTION 8.4. EQUALIZATION PROVISION. Each Bank agrees with the
         other Banks that if it, at any time, shall obtain any Advantage over
         the other Banks or any thereof in respect of the Debt (except under
         Article III hereof), it shall purchase from the other Banks, for cash
         and at par, such additional participation in the Applicable Debt as
         shall be necessary to nullify the Advantage. If any such Advantage
         resulting in the purchase of an additional participation as aforesaid
         shall be recovered in whole or in part from the Bank receiving the
         Advantage, each such purchase shall be rescinded, and the purchase
         price restored (but without interest unless the Bank receiving the
         Advantage is required to pay interest on the Advantage to the Person
         recovering the Advantage from such Bank) to the extent of the recovery.
         Each Bank further agrees with the other Banks that if it at any time
         shall receive any payment for or on behalf of Borrower on any
         indebtedness owing by Borrower to that Bank by reason of offset of any
         deposit or other indebtedness, it will apply such payment first to the
         Debt owing by Borrower to that Bank (including, without limitation, any
         participation purchased or to be purchased pursuant to this Section or
         any

                                       9

<PAGE>   10

         other Section of this Agreement), subject to the Tranche D Conditions.
         Borrower agrees that any Bank so purchasing a participation from the
         other Banks or any thereof pursuant to this Section may exercise all
         its rights of payment (including the right of set-off) with respect to
         such participation as fully as if such Bank was a direct creditor of
         Borrower in the amount of such participation.

         15. The Credit Agreement is hereby amended to delete Section 9.9
therefrom and to insert in place thereof the following:

                  SECTION 9.9. INDEMNIFICATION OF AGENTS. The Banks agree to
         indemnify Agents (to the extent not reimbursed by Borrower), in
         accordance with their Commitment Percentages applicable to the Tranche
         A Commitments from and against any and all liabilities, obligations,
         losses, damages, penalties, actions, judgments, suits, costs, expenses
         or disbursements of any kind or nature whatsoever which may be imposed
         on, incurred by or asserted against Agents in their capacity as agent
         in any way relating to or arising out of this Agreement or any Loan
         Document or any action taken or omitted by Agents with respect to this
         Agreement or any Loan Document, provided that no Bank shall be liable
         for any portion of such liabilities, obligations, losses, damages,
         penalties, actions, judgments, suits, costs, expenses (including
         attorney fees) or disbursements resulting from Agents' respective gross
         negligence, willful misconduct or from any action taken or omitted by
         Agents, or either thereof, in any capacity other than as agent under
         this Agreement.

         16. The Credit Agreement is hereby amended to delete Section 10.13
therefrom and to insert in place thereof the following:

                  SECTION 10.13. ENTIRE AGREEMENT. This Agreement, any Note and
         any other Loan Document or other agreement, document or instrument
         attached hereto or referred to herein or executed on or as of the
         Closing Date integrate all of the terms and conditions mentioned herein
         or incidental hereto and supersede all oral representations and
         negotiations and prior writings with respect to the subject matter
         hereof. This Agreement is intended to, and Borrower, Agents and the
         Banks agree that this Agreement shall, (a) constitute "Revolving Credit
         Facility" (as defined in the Indenture), and (b) be a replacement of
         the Credit Agreement dated as of April 11, 1995, as amended, among
         Borrower, KeyBank National Association (successor by merger to Society
         National Bank), as Agent, and the banking institutions listed on Annex
         1 attached thereto, and the Credit Agreement dated as of January 14,
         1998 among Borrower, KeyBank National Association, as Administrative
         Agent, The Huntington National Bank, as Co-Agent, and the banking
         institutions listed on Schedule 1 attached thereto.

         17. The Credit Agreement is hereby amended to delete SCHEDULE 1 and
SCHEDULE 2 thereof in their entirety and to insert in place thereof a new
SCHEDULE 1 and a new SCHEDULE 2, in the form of SCHEDULE 1 and SCHEDULE 2,
respectively, attached hereto.

                                       10

<PAGE>   11

         18. The Credit Agreement is hereby amended to add a new EXHIBIT F
thereto in the form of EXHIBIT F attached hereto.

         19. In connection with the fee specified in Section 2.8 of the Credit
Agreement, Borrower, Agents and the Banks agree that Borrower shall not be
obligated to pay the one-fourth percent (1/4%) increase fee set forth in such
Section 2.8 with respect to the increase of the Commitment as a result of the
addition of the Tranche D Commitments contemplated in this Second Amendment
Agreement, provided that nothing contained in this paragraph shall affect
Borrower's obligations with respect to the commitment fees relating to the
Tranche D Commitments set forth in subpart (f) of Section 2.5 of the Credit
Agreement (as amended by this Second Amendment Agreement).

         20. Concurrently with the execution of this Second Amendment Agreement,
Borrower shall:

         (a) execute and deliver to each Tranche D Bank a Tranche D Note dated
as of the Tranche D Closing Date, and such Tranche D Note shall be in the form
and substance of EXHIBIT F attached hereto;

         (b) pay to Administrative Agent, for the pro rata benefit of the
Tranche D Banks, a facility fee in the amount of One Hundred Sixty Thousand
Dollars ($160,000);

         (c) deliver to Administrative Agent a Guaranty of Payment executed by
each of Columbia Nut & Bolt Corp., Geneva Rubber Company, Industrial Fasteners
Corporation, Integrated Logistics Solutions, Inc., Integrated Logistics Holding
Company, Park-Ohio Structural Hardware LLC, Pharmaceutical Logistics, Inc., and
Pharmacy Wholesale Logistics, Inc., together with such other corporate
governance and authorization documents as requested by Agents;

         (d) cause each Guarantor of Payment to consent and agree to and
acknowledge the terms of this Second Amendment Agreement; and

         (e) pay all legal fees and expenses of Administrative Agent in
connection with this Second Amendment Agreement.

         21. Borrower hereby represents and warrants to Agents and the Banks
that (a) Borrower has the legal power and authority to execute and deliver this
Second Amendment Agreement, (b) the officers executing this Second Amendment
Agreement have been duly authorized to execute and deliver the same and bind
Borrower with respect to the provisions hereof, (c) the execution and delivery
hereof by Borrower and the performance and observance by Borrower of the
provisions hereof do not violate or conflict with the organizational agreements
of Borrower or any law applicable to Borrower or result in a breach of any
provision of or constitute a default under any other agreement, instrument or
document binding upon or enforceable against Borrower, (d) no Unmatured Event of
Default or Event of Default exists under the Credit Agreement, nor will any
occur immediately after the execution and delivery of this Second Amendment
Agreement or by the

                                       11

<PAGE>   12

performance or observance of any provision hereof, (e) Borrower is not aware of
any claim or offset against, or defense or counterclaim to, any of Borrower's
obligations or liabilities under the Credit Agreement or any Related Writing,
and (f) this Second Amendment Agreement constitutes a valid and binding
obligation of Borrower in every respect, enforceable in accordance with its
terms.

         22. Each reference that is made in the Credit Agreement or any other
writing to the Credit Agreement shall hereafter be construed as a reference to
the Credit Agreement as amended hereby. Except as herein otherwise specifically
provided, all provisions of the Credit Agreement shall remain in full force and
effect and be unaffected hereby. This Second Amendment Agreement is a Related
Writing as defined in the Credit Agreement.

         23. Borrower and each Guarantor of Payment, by signing below, hereby
waives and releases Administrative Agent, Co-Agent and each of the Banks and the
respective directors, officers, employees, attorneys, affiliates and
subsidiaries of each of the foregoing from any and all claims, offsets, defenses
and counterclaims of which Borrower or such Guarantor of Payment is aware, such
waiver and release being with full knowledge and understanding of the
circumstances and effect thereof and after having consulted legal counsel with
respect thereto.

         24. This Second Amendment Agreement may be executed in any number of
counterparts, by different parties hereto in separate counterparts and by
facsimile signature, each of which when so executed and delivered shall be
deemed to be an original and all of which taken together shall constitute but
one and the same agreement.

         25. The rights and obligations of all parties hereto shall be governed
by the laws of the State of Ohio, without regard to principles of conflicts of
laws.

                  [Remainder of page intentionally left blank.]

                                       12

<PAGE>   13

         26. JURY TRIAL WAIVER. BORROWER, AGENTS AND EACH OF THE BANKS WAIVE ANY
RIGHT TO HAVE A JURY PARTICIPATE IN RESOLVING ANY DISPUTE, WHETHER SOUNDING IN
CONTRACT, TORT OR OTHERWISE, AMONG BORROWER, AGENTS AND THE BANKS, OR ANY
THEREOF, ARISING OUT OF, IN CONNECTION WITH, RELATED TO, OR INCIDENTAL TO THE
RELATIONSHIP ESTABLISHED AMONG THEM IN CONNECTION WITH THIS AGREEMENT OR ANY
NOTE OR OTHER INSTRUMENT, DOCUMENT OR AGREEMENT EXECUTED OR DELIVERED IN
CONNECTION HEREWITH OR THE TRANSACTIONS RELATED THERETO. THIS WAIVER SHALL NOT
IN ANY WAY AFFECT, WAIVE, LIMIT, AMEND OR MODIFY AGENTS' OR ANY BANK'S ABILITY
TO PURSUE REMEDIES PURSUANT TO ANY CONFESSION OF JUDGMENT OR COGNOVIT PROVISION
CONTAINED IN ANY NOTE OR OTHER INSTRUMENT, DOCUMENT OR AGREEMENT AMONG BORROWER,
AGENTS AND THE BANKS, OR ANY THEREOF.

                                      PARK-OHIO INDUSTRIES, INC.

                                      By: _____________________________
                                          James S. Walker, Vice President

                                      and ______________________________
                                          Ronald J. Cozean, Secretary

                                      KEYBANK NATIONAL ASSOCIATION,
                                         as a Bank and as Administrative Agent

                                      By: _________________________________
                                          Kenneth M. Merhar, Vice President

                                      THE HUNTINGTON NATIONAL BANK,
                                         as a Bank and as Co-Agent

                                      By: __________________________________
                                          Timothy M. Ward, Vice President


                                       13

<PAGE>   14



                                   SCHEDULE 1


<TABLE>
<CAPTION>
       BANKING        TRANCHE A         TRANCHE B        TRANCHE C      TRANCHE A       TRANCHE D       TRANCHE D         MAXIMUM
    INSTITUTIONS      COMMITMENT       COMMITMENT       COMMITMENT       THROUGH       COMMITMENT      COMMITMENT         AMOUNT
                        AMOUNT           AMOUNT           AMOUNT        TRANCHE C        AMOUNT        PERCENTAGE
                                                                       COMMITMENT
                                                                       PERCENTAGE

<S>                  <C>               <C>              <C>                <C>         <C>                <C>          <C>
KeyBank              $50,000,000       $12,500,000      $12,500,000        50%         $25,000,000        100%         $100,000,000
National
Association

The Huntington       $50,000,000       $12,500,000      $12,500,000        50%             $0              0%           $75,000,000
National Bank

Total                $100,000,000      $25,000,000      $25,000,000       100%         $25,000,000        100%

Total                                                                                                                  $175,000,000
Commitment
Amount
</TABLE>

                                       14

<PAGE>   15

                                   SCHEDULE 2

                              GUARANTORS OF PAYMENT

Advance Vehicles, Inc.
Blue Falcon Forge, Inc.
Castle Rubber Company
Cicero Flexible Products, Inc.
Columbia Nut & Bolt Corp.
GIS Industries, Inc. (formerly known as Charken Company, Inc.)
General Aluminum Manufacturing Company II
General Aluminum Mfg. Company
Geneva Rubber Company
Industrial Fasteners Corporation
Integrated Logistics Solutions, Inc.
Integrated Logistics Solutions LLC (successor by merger to Arden Industrial
Products, Inc.)
Integrated Logistics Holding Company
Kay Home Products, Inc.
Park-Ohio Structural Hardware LLC
Pharmaceutical Logistics, Inc.
Pharmacy Wholesale Logistics, Inc.
RB&W Manufacturing LLC (successor by merger to RB&W Corporation)
The Ajax Manufacturing Company
The Metalloy Corporation
Tocco, Inc.

                                       15

<PAGE>   16

                                    EXHIBIT F

                                 TRANCHE D NOTE

$__________________                                              Cleveland, Ohio
                                                                November 1, 1999

         FOR VALUE RECEIVED, the undersigned, PARK-OHIO INDUSTRIES, INC.
("Borrower") promises to pay on the last day of the Commitment Period, as
defined in the Credit Agreement (as hereinafter defined), to the order of
_______________________ ("Bank") at the Main Office of KEYBANK NATIONAL
ASSOCIATION, as Administrative Agent, 127 Public Square, Cleveland, Ohio
44114-1306 the principal sum of

 ......................................................................   DOLLARS

or the aggregate unpaid principal amount of all Tranche D Loans made by Bank to
Borrower pursuant to Section 2.1D of the Credit Agreement, whichever is less, in
lawful money of the United States of America. As used herein, "Credit Agreement"
means the Amended and Restated Credit Agreement dated as of November 2, 1998, as
amended, among Borrower, the banks named therein, KeyBank National Association,
as Administrative Agent, and The Huntington National Bank, as Co- Agent, as the
same may from time to time be further amended, restated or otherwise modified.
Capitalized terms used herein shall have the meanings ascribed to them in the
Credit Agreement.

         Borrower also promises to pay interest on the unpaid principal amount
of each Tranche D Loan from time to time outstanding, from the date of such
Tranche D Loan until the payment in full thereof, at the rates per annum which
shall be determined in accordance with the provisions of Section 2.1D of the
Credit Agreement. Such interest shall be payable on each date provided for in
such Section 2.1D; provided, however, that interest on any principal portion
which is not paid when due shall be payable on demand.

         The portions of the principal sum hereof from time to time representing
Prime Rate Loans and LIBOR Loans, and payments of principal of any thereof, will
be shown on the records of Bank by such method as Bank may generally employ;
provided, however, that failure to make any such entry shall in no way detract
from Borrower's obligations under this Note.

         If this Note shall not be paid at maturity, whether such maturity
occurs by reason of lapse of time or by operation of any provision for
acceleration of maturity contained in the Credit Agreement, the principal hereof
and the unpaid interest thereon shall bear interest, until paid, at a rate per
annum which shall be the Default Rate. All payments of principal of and interest
on this Note shall be made in immediately available funds. In the event of a
failure to pay interest or principal, when the same becomes due, Bank may
collect and Borrower agrees to pay a late charge of an amount equal to the
greater of (a) ten percent (10%) of the amount of such late payment, or (b)
Twenty Five Dollars ($25).

                                       16

<PAGE>   17

         This Note is one of the Tranche D Notes referred to in the Credit
Agreement. Reference is made to the Credit Agreement for a description of the
right of the undersigned to anticipate payments hereof, the right of the holder
hereof to declare this Note due prior to its stated maturity, and other terms
and conditions upon which this Note is issued.

         Except as expressly provided in the Credit Agreement, Borrower
expressly waives presentment, demand, protest and notice of any kind.

         The undersigned authorizes any attorney at law at any time or times
after the maturity hereof (whether maturity occurs by lapse of time or by
acceleration) to appear in any state or federal court of record in the United
States of America, to waive the issuance and service of process, to admit the
maturity of this Note and the nonpayment thereof when due, to confess judgment
against the undersigned in favor of the holder of this Note for the amount then
appearing due, together with interest and costs of suit, and thereupon to
release all errors and to waive all rights of appeal and stay of execution. The
foregoing warrant of attorney shall survive any judgment, and if any judgment be
vacated for any reason, the holder hereof nevertheless may thereafter use the
foregoing warrant of attorney to obtain an additional judgment or judgments
against the undersigned. The undersigned agrees that Agents' or the Banks'
attorney may confess judgment pursuant to the foregoing warrant of attorney. The
undersigned further agrees that the attorney confessing judgment pursuant to the
foregoing warrant of attorney may receive a legal fee or other compensation from
Agents or the Banks.

                                     PARK-OHIO INDUSTRIES, INC.

                                     By: _____________________________
                                              James S. Walker, Vice President

                                     and ______________________________
                                              Ronald J. Cozean, Secretary



"WARNING -- BY SIGNING THIS PAPER YOU GIVE UP YOUR RIGHT TO NOTICE
AND COURT TRIAL.  IF YOU DO NOT PAY ON TIME A COURT JUDGMENT MAY
BE TAKEN AGAINST YOU WITHOUT YOUR PRIOR KNOWLEDGE AND THE
POWERS OF A COURT CAN BE USED TO COLLECT FROM YOU REGARDLESS
OF ANY CLAIMS YOU MAY HAVE AGAINST THE CREDITOR WHETHER FOR
RETURNED GOODS, FAULTY GOODS, FAILURE ON HIS PART TO COMPLY
WITH THE AGREEMENT OR ANY OTHER CAUSE."

                                       17

<PAGE>   18

                             GUARANTOR ACKNOWLEDGMENT
                             ------------------------
         Each of the undersigned consents and agrees to and acknowledges the
terms of the foregoing Second Amendment Agreement. Each of the undersigned
further agrees that the obligations of the undersigned pursuant to the Guaranty
of Payment executed by the undersigned shall remain in full force and effect and
be unaffected hereby.

                                    ADVANCE VEHICLES, INC.
                                    INTEGRATED LOGISTICS SOLUTIONS
                                       LLC (successor by merger to Arden
                                       Industrial Products, Inc.)
                                    BLUE FALCON FORGE, INC.
                                    CASTLE RUBBER COMPANY
                                    GIS INDUSTRIES, INC.,
                                       (formerly known as Charken Company, Inc.)
                                    CICERO FLEXIBLE PRODUCTS, INC.
                                    GENERAL ALUMINUM
                                      MANUFACTURING COMPANY II
                                    GENERAL ALUMINUM MFG. COMPANY
                                    KAY HOME PRODUCTS, INC.
                                    RB&W MANUFACTURING LLC (successor
                                      by merger to RB&W Corporation)
                                    THE AJAX MANUFACTURING COMPANY
                                    TOCCO, INC.
                                    THE METALLOY CORPORATION

                                    By:____________________________________
                                        James S. Walker, Vice President
                                        of each of the foregoing Companies


                                    By: ___________________________________
                                        Ronald J. Cozean, Secretary
                                        of each of the foregoing Companies


                                       18