700-R4 A/T PUMP BODY REPLACE LOW LINE PRESSURES OCCUR. GMC Truck S15 Pickup - 4WD 1985

For 1990-2009 cars

# 700-R4 A/T PUMP BODY REPLACE LOW LINE PRESSURES OCCUR

#### MODELS: LATE 1984 AND ALL 1985 LIGHT DUTY MODELS WITH 700-R4 AUTOMATIC TRANSMISSIONS

On June 28, 1984, or Julian Date 180, all models of the 1984 THM 700-R4 transmission (refer to Figure No. 1) were built using a new pump assembly to reduce pump fluid leaks. This new pump is also used on all 1985 THM 700-R4 transmission models. Refer to Figure No. 2 for identification of the casting changes and Figure No. 3 for the reference casting number locations. For identification purposes, the casting number for the new pump body is 8654303. The casting number for the new pump cover is 8654304. The pump body and cover are not serviced separately in 1982 through 1984 transmissions (prior to 1984 Julian date 180), and must be purchased as an assembly from WDDGM. 1982-84 replacement pump assemblies do, however, incor- porate all the latest changes found in the 1985 model. When replacing the pump body used on all 700-R4 transmissions beginning with 1984 Julian date 180, use service package P/N 8649950. The previously released service package, P/N 8642986, MUST NOT be used in these transmissions, as low line pressures may occur. Refer to the chart below for 1982 through 1985 model year THM 700-R4 service parts information,

#### MODEL Pump Pump Pump YEAR(S) BODY COVER ASSEMBLY ------- ---- ----- -------- 1982 through Not Not See Note 1 1984 (Julian Date Available Available 179)

1984 (Julian Date 8649950 See Note 2 Not Available 180 & After) 1985

#### Note: 1 - Use the WDDGM parts catalog for PUMP ASSEMBLY part numbers based on model application.

2 - Use the WDDGM parts catalog for PUMP COVER part number based on model application.

Refer to the appropriate Service Information Manual for removal and installation procedures.

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.