4L60E Bonded Piston Set, Forward Overrun 3-4 Clutch

This is a three-piece bonded piston set for the GM 4L60E and 4L65E, part number A74960EK, covering the forward clutch piston, the overrun clutch piston, and the 3-4 clutch piston. It fits the 1994-up 4L60E family and retrofits back to 1993-1996 units when you also update the forward clutch return spring.

Bonded means the seal is molded directly to the piston instead of riding in a groove as a separate lip seal. On the bench that saves you the fight of stretching and rolling lip seals over the piston lands, and it removes the most common reason a forward or 3-4 clutch slips after a rebuild: a rolled, nicked, or hardened lip seal. If a core came in with cracked or swollen piston seals, these drop straight in.

Reach for them when you are going through the input drum and the 3-4/overrun clutch assembly. Soak the new frictions, set the pistons with clean ATF on the bores, and air-check each clutch pack before the drum goes back together. This kit is the seal-carrying pistons only, not the return springs, frictions, or steels, so pull those from your master or banner kit.