SLIP OR LOSS OF DRIVE NEW SPRAG RACE AND HUB ASSY.

Slipping or loss of drive range condition on a 1982-86 THM 700-R4 transmission may be caused by latching of the forward clutch sprag assembly. This condition can result in belling or flaring of the reverse input housing and reaction sun shell. A new sprag, race, and hub assembly is used in production and is available for service.

Date of Change (Figure 1)

July 17, 1986, Julian date 198, a new sprag, race, and hub assembly was introduced for all 1987 THM 700-R4 transmission models. This change is also in 1987 Service Replacement Transmission Assembly (SRTA) models effective July 17, 1986, Julian date 198.

Service Action

When using the new sprag, race, and hub assembly, the sprag assembly wear plate (640) and the input carrier to race thrust washer (660) must be removed and not replaced (refer to Figure 2).

Service Parts Information

8663773 Sprag, Race, and Hub Assembly 5.0L Firebird Models 8663774 Sprag, Race, and Hub Assembly All other models

Service Manual Reference

Refer to transmission internal parts, Figure 58, 1987 THM 700-R4 unit repair section.

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.