<PAGE>
 
                        AMENDED NEGATIVE PLEDGE AGREEMENT
                        ---------------------------------

     This Amended Agreement is entered into by and among MILLER INDUSTRIES,
INC., a Tennessee corporation with its principal offices in Chattanooga,
Tennessee (the "Borrower"), CENTURY HOLDINGS, INC., a Tennessee corporation and
wholly-owned subsidiary of Borrower ("Century Holdings"), MILLER INDUSTRIES
TOWING EQUIPMENT, INC., a Delaware corporation and a wholly-owned subsidiary of
Century Holdings ("Towing Equipment"), CHAMPION CARRIER CORPORATION, a Delaware
corporation and a wholly-owned subsidiary of Century Holdings, Inc. ("Champion")
and MILLER INDUSTRIES INTERNATIONAL, INC. ("International") (Century Holdings,
Towing Equipment, Champion and International are collectively referred to herein
as "Guarantors"), and NATIONSBANK OF TENNESSEE, N.A., a national banking
association with its offices in Chattanooga, Tennessee ("NationsBank")
(hereinafter referred to as "Lender").

                              W I T N E S S E T H:
                              -------------------

     That WHEREAS, Borrower and Guarantors entered into that certain Loan
Agreement dated June 28, 1994, with NationsBank (the "Loan Agreement"); and

     WHEREAS, NationsBank issued to the Borrower a Commitment Letter providing
that NationsBank would make available to the Borrower a Revolving Line of Credit
Loan in the maximum aggregate principal amount of Fifteen Million Dollars
($15,000,000.00), depending upon the amount received by Borrower pursuant to the
Public Offering (as defined in the Loan Agreement) as more specifically set
forth in the Loan Agreement; and

     WHEREAS, pursuant to the Loan Agreement, the Lender advanced the Revolving
Line of Credit Loan (as defined in the Loan Agreement) pursuant to the terms and
conditions of the Loan Agreement, and the Borrower has used the proceeds of the
Revolving Line of Credit Loan as provided in the Loan Agreement; and

     WHEREAS, as one of the conditions of the Loan Agreement, Borrower and
Guarantors agreed to execute a Negative Pledge Agreement whereby Borrower and
Guarantors agreed that they would not sell, convey, transfer, pledge, mortgage,
grant a security interest in nor encumber in any manner any of their accounts
receivable, inventory and equipment owned by either Borrower or Guarantors,
whether now existing or acquired in the future, nor sell, convey, transfer,
pledge, mortgage, grant a security interest in nor encumber any capital stock of
the Guarantors, without the prior written consent of Lender; so long as any
Obligation (as that term is defined in the Loan Agreement) of the Borrower and
Guarantors to the Lender remains outstanding, except as specifically allowed in
the Loan Agreement (the "Negative Pledge Agreement"); and

     WHEREAS, on or about December 30, 1994, Towing Equipment and Lender entered
into an Amendment to Certain Loan Documents amending the Loan Agreement and
Negative Pledge Agreement to reflect the merger of Century Wrecker Corporation
with an 
<PAGE>
 
entity called Century Finance Group, Inc. and the name change of the merged
entities to Miller Industries Towing Equipment, Inc. and to recognize the
liability and obligation of Towing Equipment as new guarantor under the Loan
Agreement and Negative Pledge Agreement and the Loan Documents; and

     WHEREAS, on or about March 30, 1995 the Lender, Borrower and Century
Holdings, Towing Equipment and Champion (as Guarantors) entered into a Second
Amended Loan Agreement whereby the interest rate payable by Borrower to Lender
on the Revolving Line of Credit was amended; and

     WHEREAS, on or about December 29, 1995, Lender, Borrower and Guarantors
entered into a Third Amended Loan Agreement and Amendment to Guaranty Agreements
whereby the amount of indebtedness was increased from $15,000,000 to an amount
up to $25,000,000, the interest rate was amended, the financial covenants were
revised, and the Guarantors affirmed and confirmed their guaranty of the
Obligations (as defined in the Loan Agreement, as amended) of Borrower to Lender
including the increase in indebtedness to an amount up to $25,000,000; and

     WHEREAS, on or about February 29, 1996, Lender, Borrower and Guarantors
entered into a Fourth Amendment to Loan Agreement whereby the Loan Agreement was
amended to add an event of default; and

     WHEREAS, Borrower has requested and Lender has agreed to increase the
it-evolving Line of Credit Loan available to Borrower from $25,000,000 to an
amount up to $50,000,000 pursuant to a Renewal and Modification of Revolving
Line of Credit Note, and Lender, Borrower and Guarantors have entered into a
Fifth Amendment to Loan Agreement and Amendment to Guaranty Agreements to
increase the amount of indebtedness under the Revolving Line of Credit Note, to
extend the maturity date, to amend the interest rate, to revise financial
covenants and to make other amendments that will be set forth therein and to
affirm and confirm the guaranty by the Guarantors of the increase in the amount
of the indebtedness from $25,000,000 to up to $50,000,000; and

     WHEREAS, as one of the conditions to increasing the amount of indebtedness
under the Revolving Line of Credit Note, Borrower and Guarantors have agreed to
execute this Amended Negative Pledge Agreement to affirm and reaffirm Borrower
and Guarantors' agreement that they will not sell, convey, transfer, pledge,
mortgage, grant a security interest in or encumber in any manner any of their
accounts receivable, inventory and equipment owned by either Borrower or
Guarantors and any capital stock of the Guarantors, whether now existing or
acquired in the future, without the prior written consent of Lender, so long as
any Obligation (as that term is defined in the Loan Agreement) including, but
not limited to, the increase in indebtedness of up to $50,000,000, of the
Borrower and Guarantors to the Lender remains outstanding, except as
specifically allowed in the Loan Agreement, as it may be amended from time to
time; and

                                      -2-
<PAGE>
 
     WHEREAS, in consideration of the mutual covenants and conditions set forth
herein and in consideration of the Lenders increase in the Revolving Line of
Credit Loan to Borrower and Guarantors contemplated under the Fifth Amended Loan
Agreement and Amendment to Guaranty Agreements executed in relation thereto, the
legal sufficiency of which are irrevocably acknowledged, the parties hereto,
intending to be legally bound, agree as follows:

     1. All terms and condition of the Negative Pledge Agreement executed by
Borrower and Guarantors on June 24, 1994, as amended, shall remain in full force
and effect and are incorporated by reference herein and shall extend and apply
to the increase in indebtedness of Borrower to Lender from $25,000,000 to an
amount up to $50,000,000.

     IN WITNESS WHEREOF, the parties intending to be legally bound have executed
this Second Amended Negative Pledge Agreement as of this 30th day of April,
1997.
                    
                                 MILLER INDUSTRIES, INC.


                                 By:  /s/ Adam Dunayer      Vice President, CFO
                                    -------------------------------------------
                                                                        Title

STATE OF TENNESSEE         )
                           )
COUNTY OF HAMILTON         )

     BEFORE ME personally appeared Adam Dunayer, with whom I am
personally acquainted (or proved to me on the basis of satisfactory evidence),
and who, upon oath, acknowledged himself to be Vice President, CFO of Miller
Industries, Inc., the within-named corporation, and that he as such officer,
executed the foregoing instrument for the purpose therein contained, by signing
the name of the corporation by himself as such officer.

     WITNESS my hand and seal, at office, on this 23rd day of July, 1997.

                                      /s/ Nancy E. Pantee
                                      ----------------------------------------
                                      Notary Public
                                      My Commission Expires: December 11, 1999 

                                                                



                                      -3-
<PAGE>
 
                                       CENTURY HOLDINGS, INC.
   

                                       By:  /s/ Jeffrey Badgley      President
                                          -------------------------------------
                                                                         Title

STATE OF TENNESSEE         )
                           )
COUNTY OF HAMILTON         )

     BEFORE ME personally appeared Jeffrey Badgley, with whom I am
personally acquainted (or proved to me on the basis of satisfactory evidence),
and who, upon oath, acknowledged himself to be President of Century
Holdings, Inc., the within-named corporation, and that he as such officer,
executed the foregoing instrument for the purpose therein contained, by signing
the name of the corporation by himself as such officer.

     WITNESS my hand and seal, at office, on this 23rd day of July, 1997.

                                        /s/ Nancy E. Pantee
                                        ---------------------------------------
                                        Notary Public
                                        My Commission Expires: December 11, 1999
                                                           

                                      -4-
<PAGE>
 
                            MILLER INDUSTRIES TOWING EQUIPMENT,
                              INC.


                            By:  /s/ David Tatum       Vice President of Finance
                               -------------------------------------------------
                                                                           Title

STATE OF TENNESSEE         )
                           )
COUNTY OF HAMILTON         )

     BEFORE ME personally appeared David Tatum, with whom I am personally
acquainted (or proved to me on the basis of satisfactory evidence), and who,
upon oath, acknowledged himself to be VP of Finance of Miller Industries Towing,
Inc., the within-named corporation, and that he as such officer, executed the
foregoing instrument for the purpose therein contained, by signing the name of
the corporation by himself as such officer.

     WITNESS my hand and seal, at office, on this 23rd day of July, 1997.


                                       /s/ Nancy E. Pantee
                                       ------------------------------------
                                       Notary Public
                                       My Commission Expires: December 11, 1999
                                                                


                                      -5-
<PAGE>
 
                                     CHAMPION CARRIER CORPORATION


                                     By:  /s/ Jeffrey Badgley          Director
                                        ---------------------------------------
                                                                       Title

STATE OF TENNESSEE         )
                           )
COUNTY OF HAMILTON         )

     BEFORE ME personally appeared Jeffrey Badgley, with whom I am personally
acquainted (or proved to me on the basis of satisfactory evidence), and who,
upon oath, acknowledged himself to be Director of Champion Carrier Corporation,
the within-named corporation, and that he as such officer, executed the
foregoing instrument for the purpose therein contained, by signing the name of
the corporation by himself as such officer.

     WITNESS my hand and seal, at office, on this 23rd day of July, 1997.


                                       /s/ Nancy E. Pantee
                                       ------------------------------------
                                       Notary Public
                                       My Commission Expires: December 11, 1999
                                                                 

                                      -6-
<PAGE>
 
                                 MILLER INDUSTRIES, INTERNATIONAL, INC.


                                 By:  /s/ David Tatum       Assistant Secretary
                                    -------------------------------------------
                                                                          Title

STATE OF TENNESSEE         )
                           )
COUNTY OF HAMILTON         )

     BEFORE ME personally appeared David Tatum, with whom I am
personally acquainted (or proved to me on the basis of satisfactory evidence),
and who, upon oath, acknowledged himself to be Assistant Secretary of Miller
Industries International, Inc., the within-named corporation, and that he as
such officer, executed the foregoing instrument for the purpose therein
contained, by signing the name of the corporation by himself as such officer.

     WITNESS my hand and seal, at office, on this 23rd day of July, 1997.


                                       /s/ Nancy E. Pantee
                                       --------------------------------------
                                       Notary Public
                                       My Commission Expires: December 11, 1999
                                                             
                                      -7-