A/T - Revised Bearing and Roller Clutch
90pontiac12Bulletin Number: 90-7-35
Reference Number: 077111R
Publish Date: 4/90
NEW OUTPUT SHAFT/BEARING AND 3RD
Subject:
ROLLER CLUTCH ASSEMBLY FOR INCREASED LUBRICATION FLOW
Models
Affected: 1990 6000, BONNEVILLE AND GRAND PRIX MODELS W/4T60
Figure 1 - Previous And New Output Shaft/Bearing:
Figure 2:
BULLETIN COVERS: (Figures 1 and 2)
New output shaft/bearing and 3rd roller clutch assembly for increased lubricant flow. The new parts were designed to help keep the 3rd roller clutch and input sprag assemblies running cooler when overrunning. For this change to be implemented, the following parts were modified:
- The new output shaft bearing with only a single row of needle bearings instead of a double row. This makes for an easier path for the oil flow to the 3rd roller clutch and input sprag assemblies.
- The 3rd roller clutch outer race will have four less lube holes. The four lube holes are in line with the very end of the rollers. See Figure 2. Eliminating these holes helps keep the rollers from skewing or the edge of the rollers from dipping into the lube hole when overrunning, generating increased heat.
IMPORTANT: Do not try to modify the previous style parts to the new style; this may cause durability concerns.
SERVICE PROCEDURE:
Use the new output shaft/bearing and new 3rd roller clutch assembly for an obvious increased heat concern of the 3rd roller clutch or input sprag assemblies. This would include distortion of the plastic cage for the 3rd roller clutch and/or a blue race of the input sprag.
The new parts will assemble the same way as the previous parts. The new output shaft and bearing will service previous models back to the 1988 model year change for the longer output shaft required for the larger differential side gears and larger differential pinions gears in the final drive assembly. Refer to Service Bulletin HM 88-52 (Corp. Ref. No. 877132). The new 3rd roller clutch assembly will service all 1989 and 1990 models that have been equipped with an input housing thrust bearing assembly. Refer to Service Bulletin 897440-06 (Corp. Ref. No. 977109).
DATE OF PRODUCTION CHANGE:
Starting December 11, 1989 (Julian Date 345) all HYDRA-MATIC 4T60 (THM 440-T4) transaxles are built with the new 3rd roller clutch assembly.
Starting January 25, 1990 (Julian Date 025) all HYDRA-MATIC 4T60 (THM 440-T4) transaxles are built with the new output shaft/bearing.
SERVICE PARTS INFORMATION:
Part numbers 8668990 and 8675032 are expected to be available on 4-16-90. Part number 8677016 is expected to be available on 5-28-90. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be canceled as incorrectly ordered while the 400 control is in place.
SERVICE MANUAL REFERENCE:
Refer to the appropriate Service Information Manual, Section 7A1 Automatic Trans axle On-Car Service and HYDRA-MATIC 4T60 (THM 440-T4) Unit Repair Section.