INFO. ON NEW 3RD CLUTCH SPRAG ASSEMBLY

SUBJECT: INFORMATION ON NEW THIRD CLUTCH SPRAG ASSEMBLY

VEHICLES AFFECTED: 1993 "A,C,E,H,K,W" MODELS AND "U" VANS

BULLETIN COVERS:

A new design input and third clutch sprag assembly has been implemented into production in all 1993 HYDRA-MATIC 4T60 (RPO ME9) and 4T60-E (RPO M13) transaxles.

DATE OF PRODUCTION CHANGE: (Figure 1)

Effective February 1, 1993 (Julian Date 032), all HYDRA-MATIC 4T60 (RPO M13) and 4T60-E (RPO ME9) transaxles will be built with a new dual sprag assembly in place of the prior 3rd roller clutch and input sprag assembly. The 4T60-E Service Replacement Transmission Assembly (SRTA) will phase the dual sprag assembly into units beginning May 1, 1993. Future 4T60 SRTA transaxles will also contain the dual sprag assembly, but at a later, unspecified date.

Service Action: (Figure 2)

There are many differences between the prior third roller clutch and input sprag assembly and the new dual sprag assembly . Therefore, transaxles built prior to February 1, 1993 must be serviced differently than transaxles built on or after February 1, 1993.

To accommodate the new dual sprag assembly, it was necessary to modify and/or change the following components:

0 Input sprag assembly (654/665). 0 Retainer input sprag clutch (655/666). 0 Input sun gear spacer (657/667). 0 Input sun gear (658/668). 0 Input carrier assembly (662/672).

Important: None of the new modified components listed above (used in the new dual sprag assembly) are interchangeable with the prior third roller clutch and input sprag assembly. Failure to comply may result in assembly concerns and/or severe transaxle damage.

NOTE: The new dual sprag assembly can only be serviced back to 1989 (units with 10 plate third clutch packs). (All 1989 to current model 4T60/4T60-E transaxles have 10 plate third clutch packs.) Units built prior to 1989 use an 8 plate third clutch pack and have significant dimensional differences in key components.

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.