INTERMITTENT SLIP IN FORWARD AND/OR REVERSE

Models 1989 6000, BONNEVILLE AND GRAND PRIX Affected: EQUIPPED WITH THM 440-T4/HMD 4T60

BULLETIN COVERS:

An intermittent slip in forward and/or reverse when the transaxle is cold may be caused by leaking input Shaft Oil Seal Ring (s) (624) . This may be due to one or more undersized Input Shaft Oil Seal Ring(s) that seal the Input Clutch and 3rd Clutch feed holes. The transaxle may slip less in Reverse or Manual Lo (Dl) ranges (due to boosted line pressure) than in Overdrive (D4), Drive (D3), or Manual Second (D2).

SERVICE ACTION: (Figure 2) --------------- Disassemble the transaxle, remove the Shaft and Housing Assembly (626) and inspect the Input Shaft Oil Seal Rings (624) while in the grooves. The rings should take up most of the groove width. If the ring(s) only takes up about half of the groove width then replace them with rings from the package listed under Service Parts Information. Follow procedures outlin'ed in the 1989 Service Manual Unit Repair Section.

Important: Inspect for burned Input and 3rd Clutch Plate Assemblies. Replace if necessary.

SERVICE PARTS INFORMATION:

Part Number Description ----------- ------------ 8662959 Package, Overhaul Seals and Gaskets (OK Input and 3rd Clutch Plate Assemblies) 8662960 Package, Overhaul Repair Complete (For burned Input and 3rd Clutch Plate Assemblies)

Parts are currently available from GMSPO.

SERVICE NOTES:

The Oil Seal Rings may be different colors. This is just a way to tell the difference between suppliers that make the same ring.

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.