A/T - New Lube Window and Band Apply/Anchor Brackets
90chevy04GMC NUMBER: 90-7A-31
GROUP: 7A Automatic Transmission
DATE: January, 1990
CORPORATE
NUMBER: 977161
SUBJECT: 2-4 BAND CHANGES - APPLY/ANCHOR BRACKETS AND NEW LUBE WINDOW
MODELS: 1982-90 C/K, S/T, R/V TRUCKS G, M/L VANS W/4L60
Figure 1 - 2-4 Band Assembly:
BULLETIN COVERS: (Figure 1)
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.
Figure 2 - Transmission Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 2)
Starting September 8, 1989 (Juhan Date 251), all HYDRA-MATIC 4L60 transmissions were built using the new 2-4 band assembly.
SERVICE PARTS INFORMATION:
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 Pravious Part New Part
Name Number Number
Band Assembly - 2/4 8654144 8673175
Parts are currently available from GMSPO.
SERVICE MANUAL REFERENCE
Refer to the HYDRA-MATIC 4L60 Unit Repair section of the appropriate Service Manual for removal and installation of the 2-4 band.