TORSIONAL VIB WHEN TCC APPLIES SERVICE AND PARTS INFORMATION. GMC Truck S15 Pickup - 4WD 1985

For 1990-2009 cars

# TORSIONAL VIB WHEN TCC APPLIES SERVICE AND PARTS INFORMATION

#### MODELS: 1984-1987 T TRUCKS WITH 2.8L ENGINES AND THM 700-R4 AUTOMATIC TRANSMISSIONS

#### TRANSMISSION MODELS:

7TAM, 7TBM

#### BULLETIN COVERS:

A new torque converter with a 215 lb ft pressure plate will reduce driveline torsional vibration on 1984-1987 T trucks in third gear that may begin around 22 mph - 25 mph after the torque converter clutch (TCC) applies and may continue up to approximately 50 mph.

DATE OF PRODUCTION CHANGE: (Figure No.1) ------------------------- Beginning September 12, 1986 (Julian Date 255) 1987 THM 700-R4 transmission models 7TAM, 7TBM were produced with the new torque converter containing the 215 lb ft pressure plate (Figure No. 2, Item C).

#### SERVICE ACTION:

The new torque converter can be used to service any 1984-1987 THM 700-R4 transmission produced prior to September 12, 1986 (Julian Date 255) for 2.8L T truck applications only, that have a torsional vibration condition after the TCC has applied.

#### SERVICE PARTS INFORMATION:

8656908 Torque Converter Assembly, Complete.

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.