A/T - New Wave Plate Now Available

91chevy08

Number: 91-186-7A


Section: 7A


Date: February 1991


Corporate Bulletin No.: 077148


Subject: LOW AND REVERSE CLUTCH


Model and Year: 1987-91 CAPRICE, CAMARO, CORVETTE AND 1987-91 C/K, R/V, S/T TRUCKS, G, M VANS AND 1990-91 L VAN WITH 4L60 AUTOMATIC TRANSMISSION

Figure 2 - Lo And Reverse Clutch Waved Plate:

SERVICE INFORMATION: (Figure 2)


Low and Reverse Clutch failure can be caused by case casting flash interfering with clutch plate travel. A new wave plate is now available which will alleviate this condition. This new plate can be used to service any Hydra-matic 4L60 transmission produced after February 9, 1987 (Julian Date 040).


When installing the new wave plate, check for any case flash that may be present in the low and reverse grooves, and use a metal file to remove. See Figure 2 for case location information.

SERVICE PARTS INFORMATION:

Description New Part

Plate - Low and Reverse (wave) 8676362

Figure 1 - HYDRA-MATIC 4L60 Transmission Identification Information:

Part is currently available from GMSPO.

DATE OF PRODUCTION CHANGE: (Figure 1)


Beginning March 28, 1990 (Julian Date 087), all HYDRA-MATIC 4L60 transmissions were built using the new low and reverse clutch wave plate.

SERVICE MANUAL REFERENCE:

Refer to the Automatic Transmission Unit Repair Section of the appropriate service manual for low and reverse clutch plate removal and installation information.