Three new bonded pistons for the 4L60E input drum: 3-4, forward and overrun. Fits 1994-up GM units and stops apply-pressure leaks at the piston lip.
This is the three-piston set that lives in a GM 4L60E input housing: the 3-4 clutch piston (smallest diameter), the forward clutch piston (large, with the drive teeth on the outside) and the overrun clutch piston (large, with the check ball). Each one has its sealing lip bonded to the steel, so there are no loose lip seals to install or cut. They are the current 1994-up design and also drop into 4L65E and 4L70E input housings.
When a 4L60E comes in slipping in third, flaring on the 2-3 shift, or showing a burned 3-4 pack, the input drum is where you start looking. A bonded lip that has gone hard or taken a set will bleed off apply pressure, and a new 3-4 pack in a drum with a tired piston usually burns up again. If the drum is apart for a rebuild, replace all three pistons instead of reusing them.
Installation: compress the input housing return spring with a clutch spring compressor, remove the snap ring and spring assembly, and work the old pistons out. Clean the bores and check them for scoring. Lube the new lips with assembly gel or clean ATF and press each piston in straight, using a lip tool or a thin smooth wire so the lip does not roll over. Reinstall the springs and snap ring, then air check the forward, overrun and 3-4 circuits before the housing goes back into the case.
Early units: to fit these pistons in a 1982-1993 700R4 or early 4L60 housing you also need the updated return spring assembly, GM 24206085. It is not included in this set.
| Pieces | |
| Includes | |
| Fits | |
| Early 700R4 / 4L60 (1982-1993) | |
| Weight |
