A/T - New Part (4T40-E) Drive/Driven Chain & Gear
Bulletin No.: T-93-122File in Group: 7
Number: 257
Corp.Ref.No.: 377107
Date: Aug. 1993
SUBJECT:
NEW ROCKER-JOINT DRIVE LINK AND DRIVE/DRIVEN SPROCKET ASSEMBLY
MODELS AFFECTED:
1993 ALL Vehicles WITH HYDRA-MATIC 4T60-E TRANSMISSION
A new rocker-joint design drive link assembly (510/507) has been released for 1993 Hydra-Matic 4T60-E (RPO M13) transaxles. Refer to Figures 1 and 2. Due to the unique rocker-joint drive link configuration, it was necessary to change the tooth geometry on the drive and driven sprockets.
NOTE:
A rocker-joint drive link assembly cannot be used on a transaxle that previously had a round pin drive link unless the drive and driven sprockets have been updated (or vice versa).
NOTE:
If a rocker-joint link is assembled on a unit without updating the drive and driven sprocket (or vice versa), wear on the sprockets and drive link will be greatly increased. Also, drive link noise may also increase to the level that may be considered unacceptable.
Rocker-Joint Advantages Over Round Pin Drive Link Design:
^ Low friction of design permits smoother operation at high speeds.
^ Reduced chain wear.
^ Higher efficiency at continuous speeds.
The new rocker-joint desip was implemented into production on December 21, 1992 (Julian Date 356). Refer to Figures 1 and 2.
Drive/Driven Sprocket Implementation Date
37/33 Sprocket Ratio December 21, 1992
35/35 Sprocket Ratio may be implemented mid-year 1994
Identification of New Parts (Refer to Figure 3):
P/N Description Identification
8682597 Sprocket/Sleeve Assembly - Drive 37T Part Number will be in Magenta ink.
8682600 Sprocket-Driven 33 Tooth Part Number will be in Magenta ink.
8682603 link Assembly-Drive Master link will be Copper in color.
NOTE:
Magenta is a moderate to vivid purplish red or dark to strong reddish purple.
Service Part Information:
Parts are currently available from GMSPO.
Refer to the appropriate Service Information Manual - Section 7A "Automatic Transaxle On-Vehicle" for proper on-vehicle service to remove and replace a 4T60/4T60-E transaxle. Refer to Automatic Transaxle Unit Repair Section for proper disassemble and assemble procedures.
Warranty Information