EXHIBIT 99.6

         TRIPARTY  CONTINGENT  ASSIGNMENT  AGREEMENT  dated as of April 19, 2000
(the  "AGREEMENT"),  among  Capital  Auto  Receivables  Asset Trust  2000-1 (the
"TRUST"),  General  Motors  Acceptance  Corporation  ("GMAC") and MORGAN STANLEY
CAPITAL SERVICES INC. ("MSCS").

         WHEREAS, the Trust and MSCS have entered into the Primary Swap
         Agreement;

         WHEREAS, GMAC and MSCS have entered into the Secondary Swap Agreement;

         NOW, THEREFORE, the parties hereto hereby agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

         SECTION 1.01   The following terms shall have the meanings set forth
below:

         "ADDITIONAL CONTINGENT  COUNTERPARTY" means a Person with the Requisite
Rating  entering  into an  agreement  substantially  similar  to this  Agreement
pursuant to Section 2.02.

         "ASSIGNMENT  DATE" means the date upon which GMAC receives  notice from
the Trust of the  occurrence  of a  Designated  Event,  or if such date is not a
Business Day, the next succeeding Business Day.

         "DELINQUENT  PAYMENTS" means any payments owed to the Trust as a result
of  liabilities,  obligations  and duties of MSCS  pursuant to the Primary  Swap
Agreement accruing prior to the Assignment Date that have not been made by MSCS.

         A  "DESIGNATED  EVENT" shall occur if (a) one or more Events of Default
occurs under the Primary Swap Agreement with MSCS as the Defaulting  Party,  (b)
the  occurrence  of any  applicable  Termination  Event under the  Primary  Swap
Agreement in which MSCS is an Affected  Party,  if no transfer is effected under
Part 1(f)(iv) of the Schedule to the Primary Swap Agreement (or in the case of a
credit  downgrade,  no  appropriate  arrangements  pursuant to the Primary  Swap
Confirmation's credit downgrade provisions are made within 30 days) with respect
to such event and an  assignment  pursuant to Section  2.01 would  result in the
non-occurrence  of such event as it pertains to MSCS or (c) the Trust receives a
notice from MSCS pursuant to the provisions of Section 2.03 herein.

         "FALLBACK SWAP  AGREEMENT"  means the ISDA Master  Agreement,  together
with a Schedule and Confirmation, dated as of the date hereof, between the Trust
and GMAC.

         "GMAC" means General Motors Acceptance Corporation.










         "OPERATIVE SWAP AGREEMENT"  means (i) prior to the Assignment Date, the
Primary Swap Agreement and (ii) on and after the  Assignment  Date, the Fallback
Swap Agreement.

         "OPERATIVE SWAP  TRANSACTION"  means (i) prior to the Assignment  Date,
the Primary Swap  Transaction  and (ii) on and after the  Assignment  Date,  the
transaction  described  in  the  confirmation  contained  in the  Fallback  Swap
Agreement.

         "PRIMARY SWAP AGREEMENT" means the ISDA Master Agreement (including the
Schedule)  dated as of the date  hereof  between  MSCS  and the  Trust,  and the
Primary Swap Confirmation.

         "PRIMARY SWAP CONFIRMATION" means the confirmation  related to the ISDA
Master Agreement, dated as of the date hereof, between MSCS and the Trust.

         "PRIMARY  SWAP  TRANSACTION"  means the  transaction  described  in the
Primary Swap Confirmation.

         "REQUISITE RATING" means a long-term, unsecured and unsubordinated debt
rating from S&P which,  when considered  together with the long-term,  unsecured
debt rating of GMAC, would result in a Joint Rating of at least AA-.

         "SECONDARY SWAP AGREEMENT" means the ISDA Master  Agreement  (including
the Schedule  thereto),  dated as of January 15, 1998, between MSCS and GMAC and
the Secondary Swap Confirmation.

         "SECONDARY SWAP CONFIRMATION" means the confirmation dated as of the
date hereof between GMAC and MSCS, Transaction Ref. No. ______.

         "SECONDARY SWAP  TRANSACTION"  means the  transaction  described in the
Secondary Swap Confirmation.

         "SERVICER"  means GMAC or its  successor  as  servicer  pursuant to the
Trust Sale and Servicing Agreement.

         "S&P" means  Standard and Poor's  Ratings  Services,  a Division of the
McGraw-Hill Companies and any successor.

         SECTION 1.02 DEFINITIONS.  Capitalized terms used in this Agreement and
not otherwise  defined  herein shall have the meanings  specified for such terms
(i) in the Primary Swap Agreement or the Secondary Swap  Agreement,  as dictated
by its context or (ii) if not defined  therein,  in Appendix A to the Trust Sale
and  Servicing  Agreement,  dated as of April 19, 2000  between  the Trust,  the
Seller and the Servicer (the "TRUST SALE AND SERVICING AGREEMENT").

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                                   ARTICLE II

                        ASSIGNMENT UPON DESIGNATED EVENT

         SECTION 2.01  ASSIGNMENT.  In the event that a  Designated  Event shall
have occurred and is then  continuing and the Trust has notified GMAC in writing
of  such  occurrence  and  continuance  and  has  provided  evidence  reasonably
satisfactory  to  GMAC  that  a  Designated  Event  has  occurred  and  is  then
continuing,  each of the following shall  automatically  occur on the Assignment
Date:

                  (a) GMAC shall accede to rights and obligations  equivalent to
         those of MSCS under the Primary Swap Transaction in accordance with the
         terms of the  Fallback  Swap  Agreement  (including  rights,  title and
         interests and liabilities, obligations and duties accruing prior to the
         Assignment  Date). In connection with the foregoing,  in the event that
         there are Delinquent Payments, GMAC shall promptly (and in any event no
         later  than the  next  Business  Day)  make  the  full  amount  of such
         Delinquent  Payments to the Trust (but only to the extent that GMAC has
         not made a corresponding payment under the Fallback Swap Agreement). In
         the  event  that  MSCS has been  paid an  amount  corresponding  to the
         Delinquent Payments under the Secondary Swap Agreement,  MSCS agrees to
         reimburse  GMAC in an  amount  equal  to the  full  amount  of any such
         payments.  In the event that MSCS has made  payments  to the Trust as a
         result of liabilities, obligations and duties of MSCS accruing prior to
         the  Assignment  Date in  circumstances  where  GMAC  has not  made the
         corresponding payments to MSCS under the Secondary Swap Agreement, GMAC
         agrees to  reimburse  MSCS in an amount equal to the full amount of any
         such  payments.  Except as expressly  provided in the third sentence of
         this paragraph (a), on and at all times following the Assignment  Date,
         MSCS shall  have no  liabilities,  obligations  and  duties,  including
         payment  obligations of any kind, under the Primary Swap Agreement.  As
         of the Assignment Date, the Primary Swap Transaction  shall be governed
         by the terms of the  Fallback  Swap  Agreement,  and the  Primary  Swap
         Agreement shall no longer govern the Primary Swap  Transaction  (except
         with respect to rights,  liabilities,  obligations  and duties  accrued
         prior to the Assignment Date).

                  For the  avoidance  of  doubt,  on and  with  effect  from the
         Assignment  Date,  the Guarantee of Morgan Stanley Dean Witter & Co. in
         favor of the Trust under the Primary Swap Agreement shall be terminated
         and  cease  to  be  in  effect  (except  in  respect  of   liabilities,
         obligations  and duties  which may have  accrued  under such  guarantee
         prior to the Assignment Date).

                  (b) The Secondary Swap Transaction  shall be terminated on and
         as of the Assignment  Date without  further  liability or obligation of
         either party thereto,  without prejudice to those rights,  liabilities,
         obligations and duties accruing prior to the Assignment Date.

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                  (c) Upon (i) the  effectiveness of the Fallback Swap Agreement
         and (ii) the  payment  by GMAC to the Trust in a timely  fashion of all
         Delinquent  Payments,  if any, (x) the Event of Default or  Termination
         Event under the Primary Swap  Agreement  constituting  such  Designated
         Event,  if any, shall be deemed to be cured on and as of the Assignment
         Date, and (y) no Early Termination Date (as defined in the Primary Swap
         Agreement) may be designated as a result of such Designated Event.

         There shall be no breakage fees or other  termination costs or expenses
payable by the Trust to MSCS or by MSCS to GMAC in connection with an assignment
of the Primary Swap  Agreement to GMAC in accordance  with this Section 2.01 and
the termination of the Secondary Swap  Transaction as a result of the occurrence
and continuance of a Designated Event.

         SECTION 2.02 ADDITIONAL CONTINGENT COUNTERPARTY. If GMAC has acceded to
the  rights  and  obligations  of MSCS  under  the  Primary  Swap  Agreement  in
accordance with the provisions of this Article II, GMAC shall have the option to
find a Person  with the  Requisite  Rating  that will  either  (i) enter into an
assignment agreement that is substantially similar to this Agreement pursuant to
which such Person will become the  Additional  Contingent  Counterparty  or (ii)
enter  into  a swap  transaction  substantially  similar  to  the  Primary  Swap
Transaction and a contingent  assignment agreement that is substantially similar
to this  Agreement  under  which  such  Person  would  accede to the  rights and
obligations  of GMAC under the Primary Swap  Agreement  and GMAC will become the
Additional  Contingent  Counterparty.  MSCS shall  reimburse  GMAC for any costs
associated  with  finding  a  party  to  serve  as  the  Additional   Contingent
Counterparty.  Any  delay  or  inability  in  finding  a party  to  serve as the
Additional  Contingent  Counterparty  will not  result  in the  occurrence  of a
Termination  Event,  an Event of Default or otherwise lead to the designation of
an Early Termination Date under the Operative Swap Agreement.

         SECTION 2.03 NOTICE. MSCS agrees that, to the extent that it has actual
knowledge  that it will be unable to make a payment or  delivery  on a scheduled
payment date under the Primary Swap  Agreement,  it shall provide  notice to the
Trust of such  inability  at least two  Business  Days  prior to such  scheduled
payment  date.  This Section  2.03 shall not be  construed  to obligate  MSCS to
undertake any affirmative action or inquiry to ascertain whether it will be able
to make any such payment or delivery.  Any failure by MSCS to provide  notice to
the Trust of such  inability  shall be without  prejudice to MSCS's rights under
this Agreement and the Primary Swap Agreement.

                                   ARTICLE III

                                  MISCELLANEOUS

         SECTION 3.01 MISCELLANEOUS.  (a) ENTIRE AGREEMENT.  This Agreement, the
Primary Swap Agreement and the Secondary  Swap  Agreement  constitute the entire
agreement and  understanding  of the parties with respect to the subject  matter
thereof and  supersede all oral  communications  and prior  writings  (except as
otherwise provided therein) with respect thereto.

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         (b)      COUNTERPARTS.  This Agreement may be executed and delivered in
counterparts (including by facsimile transmission) each of which will be deemed
an original.

         (c)      HEADINGS.  The headings used in this agreement are for
convenience of reference only and are not to affect the  construction of or to
be taken into consideration in interpreting this Agreement.

         (d)      GOVERNING LAW.  This Agreement will be governed by and
construed in accordance with the laws of the State of New York (without
reference to choice of law doctrine).

         (e)      NOTICES. All demands,  specifications and notices to a party
hereto under this Agreement will be made pursuant to the provisions of the
Primary Swap Agreement or the Secondary Swap Agreement, as applicable.

         (f)      NO WAIVER. Notwithstanding any other provision in this
Agreement to the contrary, no full or partial failure to exercise and no delay
in exercising, on the part of any party hereto,  any right,  remedy,  power or
privilege  under this  Agreement,  regardless  of the  frequency  or constancy
of such failure or delay, shall operate in any way as a waiver thereof by such
party.

         (g)      INCONSISTENCIES.  Except as expressly provided herein, the
Primary Swap Agreement  shall not be deemed to be amended hereby in any respect.
In the event of any inconsistencies  between the provisions of this Agreement
and those of the Primary Swap  Agreement or the Secondary Swap  Agreement,  the
provisions hereof shall prevail.

         (h)      AMENDMENTS.  This Agreement may not be amended except by the
execution of a written instrument by all parties hereto.

         (i)      LIMITATION OF LIABILITY. It is expressly understood and agreed
by the parties  hereto that (a) this Agreement is executed and delivered by
Bankers Trust (Delaware),  not individually or personally but solely as Owner
Trustee of Capital  Auto  Receivables  Asset Trust 2000-1 in the exercise of the
powers and authority  conferred  and  vested  in  it,  (b)  each  of  the
representations, undertakings  and  agreements  herein  made on the part of the
Trust is made and intended not as personal representations, undertakings and
agreements by Bankers Trust  (Delaware)  but is made and intended for the
purpose for binding only the Trust, (c) nothing herein contained shall be
construed as creating any liability on Bankers Trust (Delaware), individually or
personally, to perform any covenant either expressed or implied contained
herein, all such liability,  if any, being expressly waived by the parties
hereto and by any Person claiming by, through or under the parties  hereto and
(d) under no  circumstances  shall  Bankers  Trust (Delaware) be personally
liable for the payment of any indebtedness or expenses of the  Trust  or be
liable  for  the  breach  or  failure  of any  obligation, representation,
warranty or covenant made or undertaken by the Trust under this Agreement or any
 other related documents.

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                  IN WITNESS  WHEREOF,  the parties have executed this agreement
by their duly authorized officers as of the date hereof.

                                 CAPITAL AUTO RECEIVABLES ASSET TRUST
                                 2000-1

                                 By BANKERS TRUST (DELAWARE) not in
                                 its individual capacity, but solely as trustee

                                 By:  /S/ RAYMOND DELLICOLLI
                                      -----------------------------------------
                                 Name:    Raymond DelliColli
                                 Title:   Attorney-in-Fact

                                 GENERAL MOTORS ACCEPTANCE CORPORATION

                                 By:
                                      -----------------------------------------
                                 Name:
                                 Title:


                                 MORGAN STANLEY CAPITAL SERVICES INC.

                                 By:
                                      ------------------------------------------
                                 Name:
                                 Title:




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