A/T - Loss of Drive in All Ranges
Group Ref.: TransmissionBulletin No.: 377131
Date: March, 1994
SUBJECT:
LOSS OF DRIVE IN ALL RANGES (REPLACE CARRIER PACKAGE)
MODELS:
1991-1993 CHEVROLET AND GMC C/K, R/V, P TRUCKS AND G VANS TRANSMISSION
APPLICATIONS:
1991-1993 HYDRA-MATIC 4L80-E/4L80-EHD (MT1)
(Refer to Corporate bulletin # 377114R for the 1991 and 1992 SRTA service policies and procedures.)
CONDITION:
Loss of drive in all ranges.
CAUSE:
The turbine shaft may fracture at the forward clutch feed hole due to high mileage and/or extreme service applications. In 15,000 GVW and higher applications with a three piece prop shaft system, driveline angle misalignment may cause a vibration that can affect the turbine shaft. This may also cause a transmission pump failure.
CORRECTION:
Beginning on May 5, 1993, (Julian Date 125), the turbine shaft manufacturing process was changed. The changes Included shot peening the area around the forward clutch feed hole, the feed hole diameter reduced and drilled through, the turbine shaft groove radius increased, and a chamfer added to the overdrive carrier.
Important:
GMC Truck Dealers should refer to bulletin # 367106, dated December 1993, Automatic Transmission Service Procedure Changes for In warranty repairs. Out of warranty repairs may utilize this bulletin.
SERVICE PARTS INFORMATION:
24200130 Carrier Package - Overdrive
Carrier assembly complete
Ring seals
Turbine shaft and ball assembly Turbine shaft front oil seal
Service parts are available through GMSPO.