<PAGE>

                                                                   EXHIBIT 4.2.5


                          J. B. POINDEXTER & CO., INC.

                                    As Issuer


                     UNITED STATES TRUST COMPANY OF NEW YORK

                                   As Trustee


                     THE SUBSIDIARY GUARANTORS NAMED HEREIN

                                  As Guarantors




                          FIFTH SUPPLEMENTAL INDENTURE

                         DATED AS OF SEPTEMBER 29, 2000




                         12 1/2% SENIOR NOTES DUE 2004


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         FIFTH SUPPLEMENTAL INDENTURE, dated as of September 29, 2000, (herein
called this "Supplemental Indenture") among J.B. POINDEXTER & CO., INC., a
corporation duly organized and existing under the laws of the State of Delaware
(herein called the "Company"), having its principal office at 1100 Louisiana
Street, Suite 5400, Houston, Texas 77002, each of MORGAN TRAILER MFG. CO., a New
Jersey corporation ("Morgan"), TRUCK ACCESSORIES GROUP, INC., FORMERLY KNOWN AS
LEER, INC., a Delaware corporation ("TAG"), LOWY GROUP, INC., a Delaware
corporation ("Lowy"), EFP CORPORATION, a Delaware corporation ("EFP"), MAGNETIC
INSTRUMENTS CORP., a Delaware corporation ("MIC"), RAIDER INDUSTRIES, INC., a
Saskatchewan corporation ("Raider"), KWS MANUFACTURING COMPANY, INC., a Texas
corporation ("KWS"), UNIVERSAL BRIXIUS, INC., a Wisconsin corporation
("Brixius"), MORGAN TRAILER FINANCIAL CORPORATION, a Nevada corporation
("MTFC"), and MORGAN TRAILER FINANCIAL MANAGEMENT, L.P., a Texas limited
partnership ("MTFMLP") and UNITED STATES TRUST COMPANY OF NEW YORK, a
corporation duly organized and existing under the laws of the State of New York,
United States of America, having its principal office at 114 West 47th Street,
New York, New York 10036, as Trustee (herein called the "Trustee")

                                     RECITAL

         WHEREAS, the Company, Morgan, TAG, Lowy, EFP, MIC and the Trustee are
parties to that certain Indenture, dated as of May 23, 1994 (the "Original
Indenture"), governing the Company's 12 1/2% Senior Notes due 2004 (the
"Securities") issued hereunder;

         WHEREAS, the Original Indenture was amended by the First Supplemental
Indenture dated as of May 11, 1995, by the Second Supplemental Indenture dated
as of June 26, 1995, by the Third Supplemental Indenture dated as of March 8,
2000, and by the Fourth Supplemental Indenture dated March 17, 2000 (the
Original Indenture as so amended, the "Indenture");

         WHEREAS, MTFC and MTFMLP, are Restricted Subsidiaries that, pursuant to
Section 1305 of the Indenture, wish to become Subsidiary Guarantors under the
Indenture by jointly and severally unconditionally guaranteeing the Securities
on a senior basis;

         WHEREAS, Section 901(6) of the Indenture provides that, without the
consent of any Holders, the Company, when authorized by a Board Resolution, the
Subsidiary Guarantors, when authorized by resolutions of their respective boards
of directors (certified copies of which shall be furnished to the Trustee) and
the Trustee, at any time and from time to time, may enter into one or more
indentures supplemental to the Indenture, in form satisfactory to the Trustee,
to add new Subsidiary Guarantors pursuant to Section 1305 of the Indenture;

         WHEREAS, the Company and the Subsidiary Guarantors pursuant to the
foregoing authority, propose in and by this Supplemental Indenture to amend and
supplement the Indenture in certain respects, and requests the Trustee to enter
into this Supplemental Indenture; and


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         WHEREAS, all things necessary to make this Supplemental Indenture a
valid agreement of the Company, the Subsidiary Guarantors and the Trustee and a
valid amendment of and supplement to the Indenture have been done;

         NOW, THEREFORE, for and in consideration of the premises, it is
mutually covenanted and agreed for the equal and proportionate benefit of all
Holders of the Securities:

                                   ARTICLE ONE

                             DEFINITIONS; GUARANTEE

         SECTION 1.1 Definitions. All terms used in this Supplemental Indenture
which are not defined in this Supplemental Indenture and which are defined in
the Indenture shall have the

meanings assigned to them in the Indenture.

         SECTION 1.2 Guaranty. Each of MTFC and MTFMLP hereby unconditionally,
jointly and severally with the other Subsidiary Guarantors, guarantee to each
Holder of a Security authenticated and delivered by the Trustee, and to the
Trustee on behalf of such Holder, the due and punctual payment of the principal
of (and premium, if any) and interest on such Security when and as the same
shall become due and payable, whether at the Stated Maturity Date, by
acceleration, call for redemption, purchase or otherwise, in accordance with the
terms of such Security and of the Indenture, and each of MTFC and MTFMLP agrees
that from and after the date hereof each of MTFC and MTFMLP shall be subject to
the provisions (including the representations and warranties) of the Indenture
as a Subsidiary Guarantor as fully as if each of MTFC and MTFMLP were a party to
and had executed the Indenture as a Subsidiary Guarantor.

                                   ARTICLE TWO

                                  MISCELLANEOUS

         SECTION 2.1 Incorporation of Supplemental Indenture. All provisions of
this Supplemental Indenture shall be deemed to be incorporated in, and made a
part of, the Indenture, and the Indenture, as supplemented and amended by this
Supplemental Indenture, shall be read, taken and construed as one and the same
instrument.

         SECTION 2.2 Headings. The Article and Section headings of this
Supplemental Indenture are for convenience only and shall not affect the
construction hereof.

         SECTION 2.3 Counterparts. This Supplemental Indenture may be executed
in any number of counterparts, each of which so executed shall be deemed to be
an original, but all such counterparts shall together constitute but one and the
same instrument.

         SECTION 2.4 Conflict with Trust Indenture Act. If any provision hereof
limits, qualifies or conflicts with a provision of the Trust Indenture Act that
is required under such Act



                                       2
<PAGE>

to be part of and govern this Supplemental Indenture, the latter provision shall
control. If any provision of this Supplemental Indenture modifies or excludes
any provision of the Trust Indenture Act that may be so modified or excluded,
the latter provision shall be deemed to apply to this Supplemental Indenture as
so modified or to be excluded, as the case may be.

         SECTION 2.5 Successors and Assigns. All covenants and agreements in
this Supplemental Indenture by the Company or any Subsidiary Guarantor shall
bind its respective successors and assigns, whether so expressed or not.

         SECTION 2.6 Separability Clause. In case any provisions in this
Supplemental Indenture shall be invalid, illegal or unenforceable, the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby.

         SECTION 2.7 Benefits of Supplemental Indenture. Nothing in this
Supplemental Indenture, express or implied, shall give to any Person, other than
the parties hereto, and their successors hereunder and the Holders of
Securities, any benefit or any legal or equitable right, remedy or claim under
this Supplemental Indenture.

         SECTION 2.8 GOVERNING LAW. THIS SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

         IN WITNESS WHEREOF, the parties have caused this Supplemental Indenture
to be duly executed, and their respective corporate seals to be hereunder
affixed and attested, all as of the date and year first above written.


Attest:                                   J. B. POINDEXTER & CO., INC.


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             Executive Vice President


                                          MORGAN TRAILER MFG. CO.
                                          TRUCK ACCESSORIES GROUP, INC.
                                          EFP CORPORATION
Attest:                                   MAGNETIC INSTRUMENTS CORP.


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             Vice President


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<PAGE>


Attest:                                   LOWY GROUP, INC.


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             President



                                          UNITED STATES TRUST COMPANY
Attest:                                   OF NEW YORK


                                          By:
-------------------------                    -----------------------------------



                                          RAIDER INDUSTRIES, INC.
Attest:                                   a Saskatchewan corporation


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             Vice President


Attest:                                   KWS MANUFACTURING COMPANY, INC.


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             President


Attest:                                   UNIVERSAL BRIXIUS, INC.


                                          By:
-------------------------                    -----------------------------------
                                             Stephen Magee
                                             Vice President



                                       4



<PAGE>



                                          AGREED AND ACCEPTED:

Attest:                                   MORGAN TRAILER FINANCIAL
                                          CORPORATION


                                          By:
-------------------------                    -----------------------------------
                                             Jim Mitchell
                                             President


Attest:                                   MORGAN TRAILER FINANCIAL
                                          MANAGEMENT, L.P.

------------------------                  BY: MORGAN TRAILER MFG. CO., ITS
                                              GENERAL PARTNER


                                              By:
                                                 -------------------------------
                                                 Stephen Magee
                                                 Vice President



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<PAGE>


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )


         On the _____________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Executive Vice President of J. B. Poindexter & Co., Inc., one of the
corporations described in and which executed the foregoing instrument; that he
knows the seal of said corporation; that the seal affixed to said instrument is
such corporate seal; that it was so affixed by authority of the Board of
Directors of said corporation, and that he signed his name thereto by like
authority.


                                                --------------------------------



STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Morgan Trailer Mfg. Co., one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed his name thereto by like authority.



                                                --------------------------------



                                       6

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STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Truck Accessories Group, Inc., formerly known as Leer
Inc., one of the corporations described in and which executed the foregoing
instrument; that he knows the seal of said corporation; that the seal affixed to
said instrument is such corporate seal; that it was so affixed by authority of
the Board of Directors of said corporation, and that he signed his name thereto
by like authority.


                                                --------------------------------


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _____________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is President of Lowy Group, Inc., one of the corporations described in and
which executed the foregoing instrument; that he knows the seal of said
corporation; that the seal affixed to said instrument is such corporate seal;
that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed his name thereto by like authority.


                                                --------------------------------



                                       7


<PAGE>


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of EFP Corporation, one of the corporations described in
and which executed the foregoing instrument; that he knows the seal of said
corporation; that the seal affixed to said instrument is such corporate seal;
that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed his name thereto by like authority.


                                                --------------------------------


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the ______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Magnetic Instruments Corp., one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed his name thereto by like authority.


                                                --------------------------------



                                       8

<PAGE>


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the ______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is President of KWS Manufacturing Company, Inc., one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed his name thereto by like authority.


                                                --------------------------------


STATE OF NEW YORK          )
                           )    ss.
COUNTY OF NEW YORK         )

         On the _______________ day of , 2000, before me personally came
___________________________________ to me known, who, being by me duly sworn,
did depose and say that [he - she] is ___________________________ United States
Trust Company of New York, one of the corporations described in and which
executed the foregoing instrument; that [he - she] knows the seal of said
corporation; that the seal affixed to said instrument is such corporate seal;
that it was so affixed by authority of the Board of Directors of said
corporation, and that [he - she] signed his name thereto by like authority.



                                                --------------------------------


                                       9


<PAGE>


STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the ______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Raider Industries Inc., one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board of Directors of said
corporation, and he signed his name thereto by like authority.


                                                --------------------------------



STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Universal Brixius, Inc. one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board of Directors of said
corporation, and he signed his name thereto by like authority.


                                                --------------------------------



                                       10

<PAGE>



STATE OF TEXAS             )
                           )    ss.
COUNTY OF HARRIS           )

         On the _______________ day of September 2000, before me personally came
Stephen Magee, to me known, who, being by me duly sworn, did depose and say that
he is Vice President of Morgan Trailer Mfg. Co., a New Jersey corporation and
the general partner of Morgan Trailer Financial Management, L.P., one of the
legal entities described in and which executed the foregoing instrument; that he
knows the seal of said corporation; that the seal affixed to said instrument is
such corporate seal; that it was so affixed by authority of the Board of
Directors of said corporation, and he signed his name thereto by like authority.


                                                --------------------------------


STATE OF OREGON            )
                           )    ss.
COUNTY OF CLACKAMAS        )

         On the _______________ day of September 2000, before me personally came
Jim Mitchell, to me known, who, being by me duly sworn, did depose and say that
he is President of Morgan Trailer Financial Management Corporation, one of the
corporations described in and which executed the foregoing instrument; that he
knows the seal of said corporation; that the seal affixed to said instrument is
such corporate seal; that it was so affixed by authority of the Board of
Directors of said corporation, and he signed his name thereto by like authority.


                                                --------------------------------



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