<PAGE>

                                                                   EXHIBIT 4.1.3

                             UNITED AUTO GROUP, INC.
                                   AS ISSUER,

                           THE GUARANTORS NAMED HEREIN
                                 AS GUARANTORS,

                                       AND

                         J.P. MORGAN TRUST COMPANY, N.A.
                                   AS TRUSTEE,
                           AS SUCCESSOR IN INTEREST TO
                          BANK ONE TRUST COMPANY, N.A.

                    9 5/8% SENIOR SUBORDINATED NOTES DUE 2012

                          SECOND SUPPLEMENTAL INDENTURE

                            DATED AS OF JULY 12, 2004

                                       TO

                                    INDENTURE

                           DATED AS OF MARCH 18, 2002

<PAGE>

                          SECOND SUPPLEMENTAL INDENTURE

THIS SECOND SUPPLEMENTAL INDENTURE, dated as of July 12, 2004 (this "Second
Supplemental Indenture"), to the Indenture (as defined below), among United Auto
Group, Inc., a Delaware corporation (the "Company"), the Guarantors (as defined
in the Indenture), the additional Guarantors listed on Schedule A annexed hereto
(individually, the "Additional Guarantor" collectively, the "Additional
Guarantors") and J.P. Morgan Trust Company, N.A. (as successor in interest to
Bank One Trust Company, N.A.) in its capacity as trustee (the "Trustee").

WHEREAS, each Additional Guarantor has become a Restricted Subsidiary and
pursuant to Section 901 of the Indenture is entering into this Second
Supplemental Indenture to thereby become a Guarantor as provided in Article 1013
of the Indenture; and

WHEREAS, pursuant to Section 901(e) of the Indenture, the Company, the
Guarantors, each Additional Guarantor and the Trustee may enter into this Second
Supplemental Indenture without the consent of any Holder; and

WHEREAS, all consents and notices required to be obtained and given as
conditions to the execution of this Second Supplemental Indenture pursuant to
the Indenture and all other documents relating to the Notes have been obtained
and given;

NOW, THEREFORE, for and in consideration of the premises and the mutual
covenants and agreements hereinafter set forth, the parties hereto agree as
follows:

                      ARTICLE 1: AUTHORIZATION; DEFINITIONS

SECTION 1.01. SECOND SUPPLEMENTAL INDENTURE.

This Second Supplemental Indenture is supplemental to, and is entered into, in
accordance with Section 901(e) of the Indenture, and except as modified, amended
and supplemented by this Second Supplemental Indenture, the provisions of the
Indenture are in all respects ratified and confirmed and shall remain in full
force and effect.

SECTION 1.02. DEFINITIONS.

Unless the context shall otherwise require, all terms which are defined in
Section 1.01 of the Indenture shall have the same meanings, respectively, in
this Second Supplemental Indenture as such terms are given in said Section 1.01
of the Indenture.

                        ARTICLE 2: ADDITIONAL GUARANTORS

SECTION 2.01. ADDITIONAL GUARANTORS.

Pursuant to Section 1013 of the Indenture, each Additional Guarantor hereby
expressly assumes the obligations of, and otherwise agrees to perform all of the
duties of, a Guarantor under the Indenture, subject to the terms and conditions
thereof.

                            ARTICLE 3: MISCELLANEOUS

SECTION 3.01. EFFECTIVE DATE.

This Second Supplemental Indenture shall become effective upon execution and
delivery hereof.

SECTION 3.02. COUNTERPARTS.

This Second Supplemental Indenture may be executed in several counterparts, each
of which shall be an

<PAGE>

original and all of which shall constitute but one and the same instrument.

SECTION 3.03. ACCEPTANCE.

The Trustee accepts the Indenture, as supplemented by this Second Supplemental
Indenture, and agrees to perform the same upon the terms and conditions set
forth therein as so supplemented. The Trustee shall not be responsible in any
manner whatsoever for or in respect of the validity or sufficiency of this
Second Supplemental Indenture or the due execution by the Company, the
Guarantors or each Additional Guarantor, or for or in respect of the recitals
contained herein, all of which are made solely by the Company.

SECTION 3.04. SUCCESSORS AND ASSIGNS.

All covenants and agreements in this Second Supplemental Indenture, by the
Company, the Guarantors, each Additional Guarantor or the Trustee shall bind its
respective successors and assigns, whether so expressed or not.

SECTION 3.05. SEVERABILITY.

In case any provision in this Second 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 3.06. GOVERNING LAW.

This Second Supplemental Indenture shall be governed by and construed in
accordance with the laws of the State of New York, as applied to contracts made
and performed within the State of New York, without regard to principles of
conflict of laws. Each of the parties hereto agrees to submit to the
jurisdiction of the courts of the State of New York in any action or proceeding
arising out of or relating to this Second Supplemental Indenture.

SECTION 3.07. INCORPORATION INTO INDENTURE.

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

IN WITNESS WHEREOF, the parties have caused this Second Supplemental Indenture
to be duly executed as of the date first above written.

                             UNITED AUTO GROUP, INC.

                       By:  /s/ James R. Davidson
                            ----------------------------------
                       Name:     James R. Davidson
                       Title:    Executive Vice President -
                                 Finance

Attest:  /s/ Robert H. Kurnick, Jr.
         ----------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Executive Vice President and
                      General Counsel

<PAGE>

                          UAG NORTHEAST BODY SHOP, INC.
                      LANDERS UNITED AUTO GROUP NO. 2, INC.
                               UAG SOUTHEAST, INC.
                                UAG DULUTH, INC.
                            UNITED NISSAN, INC. (GA)
                             PEACHTREE NISSAN, INC.
                               UAG TEXAS II, INC.
                                 UAG EAST, INC.
                              PALM AUTO PLAZA, INC.
                         FLORIDA CHRYSLER PLYMOUTH, INC.
                              WEST PALM NISSAN, IN.
                           NORTHLANK AUTO FINISH, INC.
                                JS IMPORTS, INC.
                            WEST PALM AUTO MALL, INC.
                        AUTO MALL PAYROLL SERVICES, INC.
                               UAG CAROLINA, INC.
                          REED-LALLIER CHEVROLET, INC.
                       MICHAEL CHEVROLET-OLDSMOBILE, INC.
                            GENE REED CHEVROLET, INC.
                               UAG GOLDSBORO, INC.
                           UAG KISSIMMEE MOTORS, INC.
                          UNITEDAUTOCARE PRODUCTS, LLC
                        UNITED AUTO FOURTH FUNDING, INC.
                         UNITED AUTO FIFTH FUNDING, INC.
                            UAG FINANCE COMPANY, INC.
                        ATLANTIC AUTO FUNDING CORPORATION
                    ATLANTIC AUTO SECOND FUNDING CORPORATION
                     ATLANTIC AUTO THIRD FUNDING CORPORATION
                          UAG HOUSTON ACQUISITION, LTD.
                        UAG INTERNATIONAL HOLDINGS, INC.
                                 UAG REALTY, LLC
                            UNITED AUTO FINANCE, INC.
                             UAG CONNECTICUT I, LLC
                           UAG ATLANTA IV MOTORS, INC.
                             UAG TULSA HOLDINGS, LLC

                        By:  /s/ James R. Davidson
                             ----------------------------------
                        Name:     James R. Davidson
                        Title:    Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         ----------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Secretary

<PAGE>

                                 UAG CHCC, INC.
                                    LRP, LTD.
                               UAG NORTHEAST, INC.
                             DIFEO PARTNERSHIP, INC.
                                UAG HUDSON, INC.
                              SOMERSET MOTORS INC.
                            LANDERS AUTO SALES, INC.
                           LANDERS BUICK-PONTIAC, INC.
                            LANDERS FORD NORTH, INC.
                            UNITED NISSAN, INC. (TN)
                               SA AUTOMOTIVE, LTD.
                               SL AUTOMOTIVE, LTD.
                                SUN MOTORS, LTD.
                        SCOTTSDALE MANAGEMENT GROUP, LTD.
                              SAU AUTOMOTIVE, LTD.
                                 SK MOTORS, LTD.
                                  KMT/UAG, INC.
                      RELENTLESS PURSUIT ENTERPRISES, INC.
                             TRI-CITY LEASING, INC.
                               HT AUTOMOTIVE, LTD.
                            WESTBURY SUPERSTORE, LTD.
                      UNITEDAUTO DODGE OF SHREVEPORT, INC.
                           COVINGTON PIKE DODGE, INC.
                          THE NEW GRACELAND DODGE, INC.
                             UAG GRACELAND II, INC.
                              UAG MEMPHIS II, INC.
                              UAG MEMPHIS IV, INC.
                               UAG MEMPHIS V, INC.
                               UAG-CARIBBEAN, INC.
                            DAN YOUNG CHEVROLET, INC.
                          YOUNG MANAGEMENT GROUP, INC.
                               UAG YOUNG II, INC.
                                UAG CLASSIC, INC.
                            CLASSIC AUTO GROUP, INC.
                         CLASSIC MANGEMENT COMPANY, INC.
                              CLASSIC IMPORTS, INC.
                            CLASSIC MOTOR SALES, LLC
                             D. YOUNG CHEVROLET LLC
                              DAN YOUNG MOTORS LLC
                          YOUNG AUTOMOTIVE HOLDINGS LLC
                            EUROPA AUTO IMPORTS, INC.
                              UAG LAKE NORMAN, LLC
                              UAG INDIANAPOLIS, LLC
                           MOTORCARS ACQUISITION, LLC
                          MOTORCARS ACQUISITION II, LLC
                         MOTORCARS ACQUISITION III, LLC
                             SCOTTSDALE FERRARI, LL
                         UAG OLDSMOBILE OF INDIANA, LLC
                               GOODSON NORTH, LLC
                            GOODSON PONTIAC GMC, LLC
                           GOODSON SPRING BRANCH, LLC
                              UAG NEVADA LAND, LLC
                                UAG CERRIOTS, LLC
                              UAG CONNECTICUT, LLC
                              UAG FAIRFIELD CA, LLC

<PAGE>

                              UAG FAIRFIELD CM, LLC
                              UAG FAIRFIELD CP, LLC
                           UAG LANDERS SPRINGDALE, LLC
                           UAG MENTOR ACQUISITION, LLC
                           UAG MICHIGAN CADILLAC, LLC
                          UAG MICHIGAN PONTIAC-GMC, LLC
                              UAG MICHIGAN T1, LLC
                              UAG MICHIGAN TMV, LLC
                               UAG PHOENIX VC, LLC
                                 UAG SPRING, LLC
                          UNITED RANCH AUTOMOTIVE, LLC
                               UAG CHEVROLET, INC.
                        BRETT MORGAN CHEVROLET-GEO, INC.
                                    HBL, LLC
                          MOTORCARS ACQUISITION IV, LLC
                                UAG NANUET I, LLC
                               UAG NANUET II, LLC
                          NISSAN OF NORTH OLMSTED, LLC
                               LANDERS NISSAN, LLC
                             UAG FAYETTEVILLE I, LLC
                            UAG FAYETTEVILLE II, LLC
                            UAG FAYETTEVILLE III, LLC

                         By:  /s/ James R. Davidson
                              ----------------------------------
                         Name:     James R. Davidson
                         Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         -------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

<PAGE>

                            DIFEO HYUNDAI PARTNERSHIP
                            DIFEO NISSAN PARTNERSHIP
                 DIFEO CHRYSLER PLYMOUTH JEEP EAGLE PARTNERSHIP
                            DIFEO LEASING PARTNERSHIP
                            DANBURY AUTO PARTNERSHIP
                            DIFEO TENAFLY PARTNERSHIP
                                 OCT PARTNERSHIP
                            HUDSON MOTORS PARTNERSHIP
                          COUNTY AUTO GROUP PARTNERSHIP
                           SOMERSET MOTORS PARTNERSHIP

                           BY: DIFEO PARTNERSHIP, INC.
                                A general partner

                         By:  /s/ James R. Davidson
                              ----------------------------------
                         Name:     James R. Davidson
                         Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         -------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

                            SHANNON AUTOMOTIVE, LTD.

                      BY: UAG TEXAS, LLC, A GENERAL PARTNER

                        By:  /s/ James R. Davidson
                             ----------------------------------
                        Name:     James R. Davidson
                        Title:    Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         ------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Secretary

<PAGE>

                            CLASSIC ENTERPRISES, LLC
                       CLASSIC NISSAN OF TURNERSVILLE, LLC

                          BY: UAG CLASSIC, INC., MEMBER

                         By:  /s/ James R. Davidson
                              ----------------------------------
                         Name:     James R. Davidson
                         Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         --------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

                               LANDERS FORD, INC.
                            NATIONAL CITY FORD, INC.
                            CENTRAL FORD CENTER, INC.
                            PIONEER FORD SALES, INC.

                           By: /s/ James R. Davidson
                               ----------------------------------
                           Name:     James R. Davidson
                           Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         --------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

<PAGE>

                           CLASSIC TURNERSVILLE, INC.
                                GMG MOTORS, INC.
                                    KMPB, LLC
                             SCOTTSDALE JAGUAR, LTD.
                           UNITED AUTO LICENSING, LLC
                                    CJNS, LLC
                              H.B.L. HOLDINGS, INC.
                        LANTZCH-ANDREAS ENTERPRISES, INC.
                                    LMNS, LLC
                                   UAG VK, LLC

                        By: /s/ James R. Davidson
                            ----------------------------------
                        Name:     James R. Davidson
                        Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         --------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

                          UAG TURNERSVILLE REALTY, LLC

                       By: /s/ James R. Davidson
                           ----------------------------------
                       Name:     James R. Davidson
                       Title:    Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         --------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Secretary

                              UAG MICHIGAN H1, LLC
                            LATE ACQUISITION II, LLC
                                UAG TULSA VC, LLC
                           UAG MICHIGAN HOLDINGS, LLC
                          UAG WEST BAY AM, LLC UAG WEST
                          BAY IA, LLC UAG WEST BAY IAU,
                            LLC UAG WEST BAY IB, LLC
                              UAG WEST BAY II, LLC
                              UAG WEST BAY IL, LLC
                              UAG WEST BAY IM, LLC
                              UAG WEST BAY IP, LLC
                              UAG WEST BAY IV, LLC
                              UAG WEST BAY IW, LLC
                              UAG WEST BAY FM, LLC

<PAGE>

                          UAG TURNERSVILLE MOTORS, LLC
                               UAG CENTRAL NJ, LLC
                               UAG ROYAL PALM, LLC
                         UAG CENTRAL FLORIDA MOTORS, LLC
                          MOTORCARS ACQUISITION V, LLC
                          BEDFORD COLLISION CENTER, LLC
                                    PMRC, LLC
                             UAG CITRUS MOTORS, LLC

                        By:  /s/ James R. Davidson
                             ----------------------------------
                        Name:     James R. Davidson
                        Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         ----------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

                             LATE ACQUISITION I, LLC

                           BY: UNITED AUTO GROUP, INC.
                                     MEMBER

                       By: /s/ James R. Davidson
                           ----------------------------------
                       Name:     James R. Davidson
                       Title:    Executive Vice President -
                                 Finance

Attest:  /s/ Robert H. Kurnick, Jr.
         -----------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Executive Vice President,
                      General Counsel

<PAGE>

                                WTA MOTORS, LTD.
                          BY: LATE ACQUISITION II, LLC
                                 GENERAL PARTNER

                          By: /s/ James R. Davidson
                              ----------------------------------
                          Name:     James R. Davidson
                          Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         ----------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

                                  UAG GN, LTD.
                                  UAG GW, LTD.
                                  UAG GD, LTD.

                        BY: UAG HOUSTON ACQUISITION, LTD.
                                 GENERAL PARTNER
                             BY: UAG TEXAS II, INC.
                                 GENERAL PARTNER

                          By: /s/ James R. Davidson
                              ----------------------------------
                          Name:     James R. Davidson
                          Title:    Assistant Treasurer

Attest: /s/ Robert H. Kurnick, Jr.
        --------------------------------
            Name:  Robert H. Kurnick, Jr.
            Title:   Assistant Secretary

<PAGE>

                                UAG CAPITOL, INC.
                                UAG CLOVIS, INC.
                                 UAG MARIN, INC.
                               UAG LOS GATOS, INC.
                               UAG SUNNYVALE, INC.
                                UAG GAVILAN, INC.
                               SIGMA MOTORS, INC.

                         By: /s/ James R. Davidson
                             ----------------------------------
                         Name:     James R. Davidson
                         Title:    Assistant Treasurer

Attest: /s/ Robert H. Kurnick, Jr.
        --------------------------------
            Name:  Robert H. Kurnick, Jr.
            Title:   Assistant Secretary

                                  UAG WEST, LLC
                                 UAG TEXAS, LLC

                        By: /s/ James R. Davidson
                            ----------------------------------
                        Name:     James R. Davidson
                        Title:    Assistant Treasurer

Attest: /s/ Robert H. Kurnick, Jr.
        --------------------------------
            Name:  Robert H. Kurnick, Jr.
            Title:   Assistant Secretary

                               UAG TORRANCE, INC.

                        By: /s/ James R. Davidson
                            ----------------------------------
                        Name:     James R. Davidson
                        Title:    Assistant Treasurer

Attest:  /s/ Robert H. Kurnick, Jr.
         --------------------------------
             Name:  Robert H. Kurnick, Jr.
             Title:   Assistant Secretary

<PAGE>

                   J.P. MORGAN TRUST COMPANY, NA, AS TRUSTEE,
                          AS SUCCESSOR IN INTEREST TO
                          BANK ONE TRUST COMPANY, N.A.

By:
     ___________________________________

Name:
Title:

<PAGE>

STATE OF NEW JERSEY )
                    ) ss.:
COUNTY OF HUDSON    )

      On the 12th day of July, 2004 before me personally came James R. Davidson
to me known, who, being by me duly sworn, did depose and say that he is employed
at One Harmon Plaza, 9th Floor, Secaucus, NJ 07094, that he is the Executive
Vice President - Finance of United Auto Group, Inc., a corporation described in
and which executed the foregoing instrument; that he holds the positions
identified on Annex I hereto with respect to each of the guarantors identified
on Annex I hereto, each of which has executed the foregoing instrument; and that
he signed his name thereto pursuant to the respective authority of the Board of
Directors of United Auto Group, Inc. and such guarantors that are corporations,
the Boards of Directors of the general partner of such guarantors that are
limited partnerships, and the members or managers of such guarantors that are
limited liability companies.

                                                (NOTORIAL SEAL)

                                                /s/ Ellen A. Shyne
                                                -------------------------------
                                                                  Notary Public

<PAGE>

                                   Schedule A

UAG Capitol, Inc.
UAG Clovis, Inc.
UAG Marin, Inc.
UAG Los Gatos, Inc.
UAG Sunnyvale, Inc.
UAG Gavilan, Inc.
Sigma Motors, Inc.

<PAGE>

<TABLE>
<CAPTION>
     GUARANTOR                  POSITION OF JAMES R. DAVIDSON
     ---------                  -----------------------------
<S>                             <C>
UAG Capitol, Inc.                    Assistant Treasurer
UAG Clovis, Inc.                     Assistant Treasurer
UAG Marin, Inc.                      Assistant Treasurer
UAG Los Gatos, Inc.                  Assistant Treasurer
UAG Sunnyvale, Inc.                  Assistant Treasurer
UAG Gavilan, Inc.                    Assistant Treasurer
Sigma Motors, Inc.                   Assistant Treasurer
</TABLE>