FLUID LEAKS FROM OIL PUMP BODY NEW SEAL ASSY.&RETAINER AVAIL.

MODELS: 1984-86 LIGHT DUTY MODELS WITH 700-R4 AUTOMATIC TRANSMISSIONS

Some 1984 through 1986 THM 700-R4 transmissions may exhibit fluid leaks from the oil pump body caused by walk-out of the pump body bushing and helix seal assembly. Several changes have been made to this area.

Beginning October 10, 1985 (Julian Date 283, see Figure No. 1) a new front pump helix seal assembly with a 270 degree lip was introduced. In addition, all THM 700-R4 transmission models incorporated a machine step (smaller bore diameter) in the oil pump effective January 6, 1986 (Julian Date 006) as shown in Figure No. 2. The latest change, effective February 11, 1986 (Julian Date 042), a new front pump seal retainer was added to eliminate walk-out of the pump body bushing and helix seal assembly.

SERVICE ACTION:

To service a 1984 (after Julian Date 180) through 1986 THM 700-R4 transmission that exhibits the subject condition, replace the pump body assembly. The new seal assembly and retainer are included with the pump body assembly or are available separately.

SERVICE PARTS INFORMATION: (Figure No. 2) ------------------------- 8649950 Pump Body Assembly (including bushing) 8648394 Seal Assembly

8654491 Seal Petainer

SERVICE MANUAL REFERENCE:

Refer to Section 7A of the appropriate light duty model service manual for Oil Pump Assembly removal procedures.

SERVICE NOTES: (Figure No. 3) ------------- The pump body bushing is included in the above pump body assembly, however, the procedure for installing a service bushing has been changed. Because of the stepped bore in the oil pump body, the bushing is now installed from the rear (using Kent-Moore tool J 34196-12) and fits tight against the step in the bore.

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.