TRANS. STUCK IN 1ST GEAR (INSTALL RETAINING RING)

SUBJECT: TRANSMISSION STUCK IN FIRST GEAR (INSTALL INPUT CARRIER TO OUTPUT SHAFT RETAINING RING)

MODELS AFFECTED: 1991-92 ROADMASTER MODELS

BULLETIN COVERS:

Some Hydra-Matic 4L60 transmissions may experience a no upshift" or "stuck in first gear" condition. This may be caused by the input carrier to output shaft retaining ring coming unseated, or retaining ring omitted during assembly. This can allow the output shaft to move slightly, and cause wear on the governor gear (the governor gear ON THE GOVERNOR, not the governor drive gear on the output shaft). The governor gear wear may be described as an "apple cored" condition. If the governor gear is worn, the transmission cannot upshift out of first gear.

SERVICE INFORMATION:

Remove the governor and inspect the governor gear. If it is "apple cored", disassemble the transmission and look for the presence of the input carrier to output shaft retaining ring.

o If the retaining ring is missing, replace it, but make sure the original retaining ring is not broken and stuck inside the transmission.

o If the retaining ring has become unseated, replace the retaining ring with a new one since the original has probably been overexpanded.

When installing a new retaining ring, be careful not to overexpand the retaining ring.

SERVICE PARTS INFORMATION:

The input carrier to output shaft retaining ring is available in several packages through GMSPO. It is included in the snap ring package, overhaul repair components package, and overhaul seals and gasket package.

SERVICE MANUAL REFERENCES:

Reference the Automatic Transmission Unit Repair Section of the appropriate service manual for retaining ring installation information.

645A PLATE ASM.,3RD & 4TH CLUTCH (FIBER) 654B PLATE, 3RD & 4TH CLUTCH (STEEL) 654C PLATE, 3RD & 4TH CLUTCH (STEEL) 655 PLATE,3RD & 4TH CL. BACKING (SEL.) 656 RING, 3RD & 4TH CL BACKING PLATE RETAINER 657 BUSHING, INPUT SUN GEAR (FRONT) 658 GEAR, INPUT SUN 659 BUSHING, INPUT SUN GEAR (REAR) -)661 RET., OUTPUT SHAFT TO INPUT CARRIER 662 CARRIER ASM., INPUT (COMPLETE) 663 BEARING ASM., THRUST (INPUT CARRIER TO REACTION SHAFT) 659 BUSHING, INPUT SUN GEAR (REAR) 661 RET., OUTPUT SHAFT TO INPUT CARRIER 662 CARRIER ASM., INPUT (COMPLETE) 663 BEARING ASM., THRUST (INPUT CARRIER TO REACTION SHAFT) 664 GEAR, INPUT INTERNAL 665 BUSHING, REACTION CARRIER (FRONT) 666 SHAFT, REACTION CARRIER 667 BUSHING, REACTION CARRIER (REAR) 668 RING, REACTION SHAFT/INTERNAL GEAR RETAINER 669 WASHER, THRUST (REACTION SHAFT/SHELL)

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.