A/T - Harsh 1 to 2, 2 to 3, or 3 to 4 Upshifts

Group Ref.: Transmission

Bulletin No.: 477102

Date: March, 1994

SUBJECT:
HARSH 1-2, 2-3 AND 3-4 UPSHIFTS (REPAIR ACCUMULATOR VALVE(S) IN CONTROL VALVE BODY)

MODELS:

1991 BUICK REATTA
1991-93 BUICK RIVIERA
1991-94 BUICK PARK AVENUE AND REGAL
1992-94 BUICK LE SABRE
1994 BUICK CENTURY AND SKYLARK
1991-93 CADILLAC ELDORADO, SEVILLE, SIXTY SPECIAL AND
FLEETWOOD (FWD)
1991-94 CADILLAC DE VILLE
1991-94 CHEVROLET LUMINA
1992-94 CHEVROLET LUMINA APV
1994 CHEVROLET BERETTA AND CORSICA
1991-92 OLDSMOBILE TORONADO AND TROFEO
1991-94 OLDSMOBILE NINETY EIGHT AND CUTLASS SUPREME
1992-94 OLDSMOBILE EIGHTY EIGHT AND SILHOUETTE
1994 OLDSMOBILE CUTLASS CIERA AND ACHIEVA
1991-94 PONTIAC GRAND PRIX
1992-94 PONTIAC BONNEVILLE AND TRANS SPORT
1994 PONTIAC GRAND AM

TRANSAXLE APPLICATIONS:
HYDRA-MATIC 4T60-E (RPO M13)

CONDITION:
Some owners may experience a harsh 1-2, 2-3 or 3-4 upshift condition. The harsh upshift condition will usually be noticeable during a light to medium throttle upshift.











CAUSE:
(Figures 1, 2 and 3) The harsh upshift condition may be caused by:

- A missing or loose accumulator bushing retainer.

- A metal shaving (burr) or debris in the accumulator valve train in the control valve body.

IMPORTANT:
All 4.9L models and 3.1L models 3BHW and 4AFW have a 1-2 accumulator valve train and piston/spring line up that is different from all other 4T60-E models. Do not assume that these models have a harsh shift condition due to misassembly. Figures 2 and 3 correctly show the 1-2 accumulator components for these models. The 1993 and 1994 HYDRA-MATIC 4T60-E AUTOMATIC TRANSAXLE UNIT REPAIR Section 7A-5B is incorrect.

CORRECTION:
(Figures 2 and 3) To repair this condition, inspect the control valve body for the following:

Accumulator bushing retainers for being present and securely installed. If a retainer is missing, refer to SERVICE PART INFORMATION for retainer part numbers.

Accumulator valve train in the control valve body for binding due to burrs or debris. Disassemble and clean the control valve body if burrs or debris are found.








SERVICE PART INFORMATION: (Figure 4)

The accumulator bushing retainer design was changed AFTER the start of the 1993 model year. Previous and current design accumulator bushings and retainers are not interchangeable. To determine the correct accumulator retainer bushing to order for 1993 model transaxles, inspect one of the other accumulator bushing retainers that is present in the control valve body. Compare with Figure 2 to determine the correct part number to order.

Parts are currently available from GMSPO.

WARRANTY INFORMATION:
For vehicles repaired under warranty, use:

Labor Operation: K6570

Labor Time: Use published labor operation time.








Legend for Figures 2, 3 and 4