A/T - 4L60 New Output Shafts and Shaft Seals

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GMC NUMBER: 91-7A-134

GROUP: 7A Automatic Transmission


DATE: August, 1991

CORPORATE NUMBER: 177118


SUBJECT: NEW OUTPUT SHAFTS AND INPUT HOUSING TO OUTPUT SHAFT SEAL 1982-91 4L60/THM 700-R4 TRANSMISSIONS

MODELS: 1982-91 S/T, C/K, R/V, G, L, M LIGHT TRUCKS AND VANS


HYDRA-MATIC 4L60 output shafts and input housing to output shaft seals have been revised to provide increased lube flow. Since lube hole locations have changed, the input housing to output shaft seal has been revised to accommodate them.

DATE OF PRODUCTION CHANGE:
Beginning January 28, 1991 (Julian Date 028), all HYDRA-MATIC 4L60 transmissions were built using the new output shafts and seals.

Figure 1:

SERVICE INFORMATION: (See Figure 1) The NEW SEAL can only be used on the NEW OUTPUT SHAFTS. If the new seal is used on a previous model output shaft, the seal will block one of the lube passages.

The previous seal can be used on both the new and previous output shafts.

The new output shafts and seal will service any HYDRA-MATIC 4L60/THM 700-R4 transmission ever built.


The new output shafts can be identified by lube hole location. They have a lube hole on the chamfer at the front of the output shaft. The lube hole was previously located on the shank of the output shaft.

SERVICE PARTS INFORMATION:
The new output shafts and seals will become available for service as current stock is depleted at GMSPO.

Reference the GMSPO parts catalog for the correct output shaft to order for your specific transmission application.

SERVICE MANUAL REFERENCE:
Refer to the Automatic Transmission Unit Repair Section of the appropriate service manual for output shaft and seal removal and installation information.