Grand Prix V6-3100 3.1L MFI VIN M (1994)
CAUSE (Figures 1 and 2)
The harsh 1-2 upshift may be caused by one of the following:
^ A binding 1-2 accumulator piston in the accumulator housing.
^ A missing or loose accumulator bushing retainer.
^ A metal shaving (burr) or debris in the 1-2 accumulator secondary valve train in the control valve body.
Important:
3BHW, 4AFW and 5AFW models have a 1-2 accumulator primary valve train and 1-2 accumulator piston/spring line up that is different from most
4T60-E models. Do not assume that these models have a harsh shift condition due to misassembly. Figures 1 and 2 correctly show the 1-2
accumulator components for these models. The 1993 and 1994 Service Manual Section 7A-5B is incorrect. The 1995 Service Manual Section 7A-5B
does correctly show the 1-2 accumulator components.
CORRECTION (Figures 1 and 2)
To repair this condition, perform the following procedure:
1. Remove and disassemble the 1-2 and 2-3 accumulator housing assembly and inspect for the 1-2 accumulator piston being stuck or binding in the
bottom of the accumulator bore.
^ If the accumulator piston is stuck in the bore, replace the accumulator housing. Refer to SERVICE PARTS INFORMATION.
^ Refer to the appropriate Service Manual for specific repair procedures.
2. If the 1-2 accumulator was not stuck in the accumulator housing, remove the control valve body and inspect for a missing retainer on the 1-2
accumulator primary or secondary valve bushing assemblies.
^ Replace any missing retainers. Refer to SERVICE PARTS INFORMATION.
^ Refer to the appropriate Service Manual for specific repair procedures.
3. If the 1-2 accumulator primary or secondary valve bushing assemblies were not missing a retainer, disassemble the 1-2 accumulator primary and
secondary valve and bushing assemblies and inspect for a binding or stuck valve due to sediment or burrs.
^ Clean the control valve body if burrs or debris are found.
^ If the valve or bushing are damaged beyond repair, replace the control valve body assembly. Refer to SERVICE PARTS INFORMATION.
