A/T - New 2-4 Band Apply, Anchor Brackets, Lube Window
90chevy03Number: 90-121-7A
Section: 7A
Date: December 1989
Corporate Bulletin No.: 977161
Subject: 2-4 BAND CHANGES-APPLY/ANCHOR BRACKETS AND NEW LUBE WINDOW
Model and Year: 1982-90 LIGHT DUTY TRUCKS WITH 4L60 (700-R4) AUTOMATIC TRANSMISSION
Figure 1 - 2-4 Band Assembly:
Figure 2 - THM 700-R4/HYDRA-MATIC 4L60 Transmission Identification Information:
TO: ALL CHEVROLET DEALERS
This bulletin covers a new HYDRA-MATIC 4L60 transmission 2-4 band with changes to the apply and anchor brackets, locating tabs, and the addition of a "lube window." The lube window was added to direct lubricating transmission fluid to the band friction material while the band is not applied. Structural changes to the apply and anchor brackets increase their durability and the locating tabs were added to aid in assembly. (See Figure 1.)
Starting September 8, 1989 (Julian Date 251), all HYDRA-MATIC 4L60 transmissions were built using the new 2-4 band assembly. (See Figure 2.)
The new band is interchangeable with the previous band and should be used for service whenever possible. As soon as the previous bands are used up, the new bands will become available.
Part Name Previous Part Number New Part Number
Band Assembly - 2/4 8654144 8673175
Parts are currently available from GMSPO.
Refer to the HYDRA-MATIC 4L60 Unit Repair section of the appropriate Service Manual for removal and installation of the 2-4 band.