SMU-SEC 7A-TRANS. UNIT REPAIR UPDATE 3-4 CLUTCH

SUBJECT: TRANSMISSION UNIT REPAIR/UPDATED 3-4 CLUTCH/REVISED FIBER PLATE USAGE

MODELS/YEARS: 1991-92 CUSTOM CRUISER AND 1991-93 BRAVADA EQUIPPED WITH THE HYDRA-MATIC 4L60 (MD8) OR 4L60-E (M30) TRANSMISSION

NEW PRODUCT INFORMATION FOR 1993 HYDRA-MATIC 4L60-E TRANSMISSIONS:

This information has been updated since publication of the 1993 Service Manual and should be noted accordingly. Be certain to familiarize yourself with these updates to properly repair the 1993 HYDRA-MATIC 4L60-E transmissions.

DATE OF PRODUCTION CHANGE:

On January 05, 1993 (Julian Date 005) HYDRA-MATIC 4L60-E transmissions were built with an improved design 3-4 clutch. The improved design consisted of combining the 3rd and 4th clutch ring retainer plate (111. 652), the 3rd and 4th clutch apply (stepped) plate (111. 653) and the 3rd and 4th clutch (steel) plate (111. 654C) into one 3rd and 4th clutch apply plate (111. 653) Figure 1. The 3rd and 4th clutch steel plates are also thicker and the backing plate selection has changed as noted in Figure 2.

FIBER PLATE USAGE FOR 1991-92 4L60 OVERHAUL KITS:

In the overhaul repair kits for the HYDRA-MATIC 4L60 there are two (2) sets of 3rd and 4th clutch fiber plates. The two 3rd and 4th clutch fiber plates are calibration sensitive and interchanging the wrong plates may cause premature failure. The following chart shows which models should use the plates labeled "2050" Figure 3.

1991 1992

1AAM 2ADM 1APM 2AKM 1CNM 2BFM 1CYM 2CHM 1FYM 2CJM 1KWM 2FUM lLHM 2KJM 1RCM 2LHM 1RDM 2WCM lYHM 2YCM 2YDM

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.