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                                                                    Exhibit 10-t

September 7, 2004

Mr. S. Carl Soderstrom, Jr.

Dear Carl:

Subject:  Mutually Agreed Upon Separation

This letter confirms the substance of our conversation regarding a mutually
agreed upon separation between you and the Company. As per our conversation, you
will remain in your current position as Senior Vice President and Chief
Financial Officer, until such time as your successor is named. Upon the naming
of your successor, you agree to resign as an officer of the Company. You also
agree to provide transitional services as may reasonably be required. We
emphasize that your acceptance of this agreement is completely voluntary.
ArvinMeritor agrees to provide you the following:

      1.    Beginning January 1, 2005, through December 31, 2007 (the
            "Separation Period"), you will receive separation pay equal to
            thirty-six months of pay (at your current compensation rate of
            $435,000 annually), spread equally over the Separation Period. The
            Separation Period is inclusive of vacation. Your Separation Period
            will be treated as credited service under the ArvinMeritor
            Retirement Plan.

      2.    You will be eligible to receive an incentive compensation plan (ICP)
            payment for fiscal year 2005 on a prorated basis (3 months out of
            12) for time worked during the fiscal year. Such payment will be
            subject to the applicable formula. Final award determination, if
            any, is subject to Board of Directors' approval.

      3.    You will be eligible to receive long term incentive plan (LTIP)
            payments based on your grant letters for FY2003-2005 and FY2004-2006
            plan years as follows:

            -     FY2003-2005 LTIP will be paid in December, 2005, pending Board
                  of Directors' approval based on the applicable formulas, on a
                  pro-rated basis (27 months out of 36) for time worked during
                  the performance cycle.

            -     FY2004-2006 LTIP will be paid in December, 2006, pending Board
                  of Directors' approval, based on the applicable formulas on a
                  prorated basis (15 months out of 36) for time worked during
                  the performance cycle.

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Mr. S. Carl Soderstrom, Jr.
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September 7, 2004

      4.    All outstanding stock options will continue to vest through your
            Separation Period. Stock options can be exercised up to three months
            after the last day of your Separation Period. Any option not
            exercised by March 31, 2008 will be forfeited.

      5.    You received a grant of restricted stock in exchange for cancelled
            options on July 16, 2001. These restricted shares and the associated
            shares purchased with reinvested dividends, will vest on July 16,
            2006. However, if the Company achieves performance objectives set
            forth in the Restricted Stock Agreement these restricted shares and
            the associated shares purchased with reinvested dividends will vest
            on January 3, 2005 or January 3, 2006.

      6.    You also received two grants of performance contingent restricted
            shares. The first grant occurred on November 22, 2002, and the
            second grant occurred on January 2, 2004. The restrictions on these
            restricted shares will not lapse until after the corresponding LTIP
            performance cycles (FY2003-2005) (FY2004-2006), are completed and
            the Compensation and Management Development Committee of the Board
            of Directors determines the extent to which the restricted shares in
            the aforementioned grants and the associated shares purchased with
            reinvested dividends will vest as set forth in the Restricted Stock
            Agreement.

      7.    Your present Company vehicle may be driven at Company expense
            through the end of your lease period, June 28, 2005, at which time
            you may purchase it in accordance with the Company Car Policy as
            though you were an active employee.

      8.    You will continue to be provided financial counseling reimbursement
            at your current annual rate through your Separation Period.

      9.    Short and long term disability coverage will cease as of December
            31, 2004.

      10.   Medical, dental, vision and flexible spending account coverage will
            remain in force through December 31, 2007. After December 31, 2007,
            you will be entitled to continue your group medical, dental, vision
            and flexible spending account coverage at your own expense for a
            period of up to 18 months through COBRA. Information as to the cost
            of such coverage will be supplied following the expiration of
            benefits. Basic life and accidental death and dismemberment coverage
            will remain in force through December 31, 2007 and the life
            insurance coverage only may be converted to an individual policy
            within 31 days after termination of coverage by contacting
            Prudential at 800-778-3827. Payroll deductions for any optional life
            insurance and/or supplemental accidental death and dismemberment
            insurance coverage that you may have elected will continue through
            December 31, 2007. Prudential will contact you through the mail
            following that date with regard to your ability to convert these
            coverages to an individual policy.

      11.   You may continue to submit your Great Oaks Country Club expenses to
            the Company for reimbursement, during your Separation Period.

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Mr. S. Carl Soderstrom, Jr.
Page 3
September 7, 2004

      12.   You will be eligible to continue to participate in the Company
            savings plan through the Separation Period. As a designated
            participant in the ArvinMeritor Supplemental Savings Plan you have
            made an irrevocable contribution election for 2004. If you wish to
            change the direction of your investments or your contribution level
            for 2005 or later, you will need to call T. Rowe Price at
            1-800-922-9945.

      13.   You will receive Company sponsored outplacement assistance from the
            outplacement firm of your choice under the executive management
            program.

      14.   Your compensation checks will be mailed to your home or direct
            deposited unless you specify otherwise. Please let us know in
            writing if you change your address.

      15.   You will not disparage, portray in a negative light, or take any
            action which would be harmful to, or lead to unfavorable publicity
            for, the Company or its subsidiaries or divisions, or any of its or
            their current or former officers, directors, employees, agents,
            consultants, contractors, owners, divisions, parents or successors,
            whether public or private, including without limitation, in any and
            all interviews, oral statements, written materials, electronically
            displayed materials and materials or information displayed on
            Internet- or intranet-related sites. In the event of a breach or
            threatened breach of this paragraph 16, you agree that the Company
            will be entitled to injunctive relief in a court of appropriate
            jurisdiction to remedy any such breach or threatened breach and you
            acknowledge that damages would be inadequate and insufficient.

      16.   You will deliver promptly to the Company (and not keep in your
            possession or deliver to any other person or entity) any and all
            property belonging to the Company in your possession or under your
            control, including without limitation, credit cards, software, palm
            pilots, pagers, other electronic equipment, records, data, notes,
            reports, correspondence, financial information, customer files and
            information and other documents or information (including any and
            all copies of such Company property). You may, however, retain your
            computer hardware.

      17.   You agree, on behalf of yourself, your heirs, executors,
            administrators and assigns, to release, acquit and forever discharge
            the Company and its subsidiaries and divisions and its and their
            respective current and former officers, directors, employees,
            agents, owners, affiliates, successors and assigns (the "Company
            Released Parties") of and from any and all manner of actions and
            causes of action, suits, debts, damages, dues, accounts, bonds,
            covenants, contracts, agreements, judgments, charges, claims, rights
            and demands whatsoever, whether known or unknown ("Losses"), which
            you, your heirs, executors, administrators and assigns ever had, now
            have or may hereafter have, against the Company Released Parties or
            any of them arising out of or by reason of any cause, matter or
            thing whatsoever from the beginning of the world to the date hereof,
            including without limitation, any and all matters relating to your
            employment by the Company and its predecessors and the cessation
            thereof, any and all matters relating to your compensation and
            benefits by or from the Company and its predecessors and any and all
            matters arising under any federal, state or local statute, rule,
            regulation or principle of contract law or common law.

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Mr. S. Carl Soderstrom, Jr.
Page 4
September 7, 2004

            You understand that as a result of this paragraph 17, you will not
            have the right to assert that the Company unlawfully terminated your
            employment or violated any of your rights in connection with your
            employment.

            You affirm that you have not filed, and agree not to initiate or
            cause to be initiated on your behalf, any complaint, charge, claim
            or proceeding against the Company Released Parties before any
            federal, state or local agency, court or other body relating to your
            employment, the cessation thereof or any other matters covered by
            the terms of this paragraph 17, and agree not to voluntarily
            participate in such a proceeding.

      18.   The Company and you agree that the terms and conditions of this
            Letter Agreement are confidential and that neither party will
            disclose the terms of this Letter Agreement to any third parties,
            other than (i) disclosure by you to your spouse, (ii) disclosure by
            the Company or you to its or your respective attorneys, auditors,
            financial advisors and accountants, (iii) as may be required by law
            (including securities laws) or (iv) as may be necessary to enforce
            this Letter Agreement. Without limiting the generality of the
            foregoing, you acknowledge that the Company may, to the extent
            required by applicable law, describe or incorporate the terms of
            this Letter Agreement in, and/or file or incorporate this Letter
            Agreement as an exhibit to, one or more filings with the Securities
            and Exchange Commission.

      19.   ArvinMeritor shall have the right to terminate this agreement at any
            time if you materially breach any of the obligations stated herein
            under this agreement.

      20.   You acknowledge that you have been advised to consult with an
            attorney prior to signing this agreement. You also acknowledge,
            understand and agree that this agreement is voluntarily entered into
            by you in consideration of the undertakings by ArvinMeritor as set
            forth herein and is consistent in all respects with the discussions
            by ArvinMeritor personnel with you relating to your separation.

      21.   You agree that for a period of eighteen months following the date of
            your departure (January 1, 2005) from the Company, you will not join
            or start a business that competes with ArvinMeritor, nor will you
            provide consultancy services, nor for the same eighteen month period
            will you solicit for employment any ArvinMeritor related employee,
            unless permission to do so is granted to you in writing by
            ArvinMeritor's CEO or his designee. Notwithstanding the foregoing,
            specific companies that would be deemed as competing against
            ArvinMeritor are: Borg-Warner Automotive, Inc.; Cummins Engine,
            Inc.; Dana Corporation; Delphi Automotive Systems; Eaton
            Corporation; Johnson Controls, Inc.; Lear Corporation; Superior
            Industries International; Tenneco Automotive, Inc.; Tower
            Automotive, Inc.; and Visteon Corporation.

            In the event there is any question as to direct or indirect
            competition, you agree to obtain approval from ArvinMeritor in
            writing prior to commencement of employment with the company which
            could be in competition. You also agree that you will not disclose,
            nor will you use any ArvinMeritor proprietary information.

      22.   This agreement is a complete and final agreement between
            ArvinMeritor and its successors and S. Carl Soderstrom, Jr., and
            supercedes all other offers, agreements,

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Mr. S. Carl Soderstrom, Jr.
Page 5
September 7, 2004

            and negotiations except for the Invention Assignment and Arbitration
            Agreements which remain in full force.

      23.   You will have until October 22, 2004, in which to consider this
            agreement, and you may revoke this agreement within seven days of
            signing. This agreement will not become effective until the
            revocation period has expired.

Sincerely,

/s/ Ernest T. Whitus
Ernest T. Whitus

Senior Vice President - Human Resources

cc:      C. McClure
         V. Baker, II

                                                Accepted and Agreed by:

                                                /s/ S. Carl Soderstrom
                                                --------------------------------
                                                S. Carl Soderstrom, Jr.

                                                September 7, 2004
                                                Date