HARSH 1-2 AND/0R 3-4 SHIFTS SOME MODEL THM 200-4R TRANS.

MODELS AFFECTED: 1984 DEVILLES AND BROUGHAMS

Some 1984 Devilles and Broughams equipped with THM 200-4R transmissions may exhibit a harsh 1-2 and/or 3-4 shift. This harsh 1-2 and/or 3-4 shift may be caused by a damaged or mispositioned TV Boost valve spring. (Refer to item #49 on page 200-4R-57 of the 1984 Service Information Manual.)

Starting on April 25, 1984 (Julian date 116) on AA models and May 8, 1984 (Julian date 129) on OM models (refer to Figure 1), a new control valve assembly which has a new TV Boost valve spring went into production on 1984 model THM 200-4R transmissions to fix this barsh 1-2 and/or 3-4 shift.

On transmissions built before the listed Julian dates, if a condition of harsh 1-2 and/or 3-4 shift is experienced and the cause is the damaged or mispositioned TV Boost valve spring, use the appropriate, new control valve assembly as listed below:

New Control Valve Assembly Model and Part Number Applications

CONTROL VALVE ASSEMBLY MODELS PART NUMBERS ------ ------------- AA,AP 8639343 OM 8639915

For warranty purposes, use labor Operation Number K6560 at .9 hour.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.