700-R4 A/T PUMP BODY REPLACE LOW LINE PRESSURES OCCUR. GMC Truck S15 Pickup - 4WD 1984

For 1990-2009 cars

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

#### VEHICLES AFFECTED: Late 1984 & All 1985 THM 700-R4 Model Transmissions

On June 28, 1984, or Julian Date 180, all models of the 1984 THM 700-R4 transmission (refer to Figure 1) were built using a new pump assembly to reduce pump fluid leaks. This pump change is also used on all 1985 THM 700-R4 tranamission models. Refer to Figure 2 for identification of the casting changes and Figure 3 for the reference casting number locations.

When replacing the new pump body that is used on all 1985 THM 700-R4 transmissions, use service package part number 8649950. The previously released service package, part number 8642986 MUST NOT be used in 1985 model transmissions as low line pressures may occur.

The pump body and cover are not serviced separately in 1982 through 1984 THM 700-R4 transmissions. Refer to the chart below for 1982 through 1985 model year THM 700-R4 service parts information.

#### Model Year(s) Pump Body Pump Cover Pump Assembly ------------- ---------- ---------- ------------- 1982 through Not Not See Note 1 1984 Available Available

1985 8649950 See Note Not Available

Notes: 1- Use the parts catalogue for Pump Assembly part numbers based on model application.

2- Use the parts catalogue for Pump Cover part numbers 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.