New 1-2 and reverse band assemblies went into production on July 2, 1990 (Julian Date 183) and have superseded previously available service parts. Because of a new manufacturing process, all the 1-2 bands are the same size and all the reverse bands are the same size, eliminating the need for selective band apply pins. There is no longer a need to measure for selective band apply pins for the entire normal service life of the band.
When installing these new bands in 1985-1990 Hydra-Matic 4T60 transaxles, it will be necessary to replace the original selective band apply pin with a new nonselective band apply pin which must be ordered separately. An instruction sheet will be included with the new reverse and 1-2 band packages that has information on the apply pins.
The following service parts are currently available from GMSPO:
P/N Description Usage Supersedes ------- ------------------------- --------- ---------- 8675986 Package - Reverse Band Assembly 1985-1990 4T60 8668012 o Reverse Band Assembly 8675152 o Instruction Sheet
8656543 Pin - Reverse Band Apply 1985-1990 4T60 o Nonselective
8675987 Package - 1-2 Band Assembly 1985-1990 4T60 8658478 o 1-1 Band Assembly 8668984 o Instruction Sheet
8656540 Pin - 1-2 Band Apply 1985-1990 4T60 o Nonselective
If replacing a 1-2 band assembly with the new 1-2 band listed in this bulletin, it will be necessary to remove the 1-2 band stop (on models so equipped). Refer to Service Bulletin T-89-135, Group 7, for 1-2 band stop removal procedure. The apply pin engagement area on the new 1-2 band is almost twice as wide as the previous style. This increased area makes for a larger "target" for the 1-2 band apply pin and eliminates the need for the 1-2 band stop. Transaxles built before January 16, 1990 (Julian Date 016) were built with a band stop and with a selective 1-2 band and apply pin. Transaxles built between January 16, 1990 (Julian Date 016) and July 2, 1990 (Julian Date 183) were built without a band stop but still with a selective 1-2 band and apply pin.
If replacing a reverse band assembly, the new reverse band also has the new friction material that will help decrease reverse engagement concerns. Refer to Cadillac Service Bulletin T-90-89, Group 7. Refer to the appropriate Cadillac Service Information Manual for the required service 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.