Accumulator piston scuffing and bore wear are common issues in Chrysler 45RFE, 545RFE, 65RFE, 66RFE and 68RFE valve bodies, especially when running increased pressures. The OE accumulator pistons have two seal rings. The seal groove at the open end of the piston is a larger diameter, with the seal ring acting as a guide to prevent piston-to-bore contact. The seal groove at the closed end of the piston is a smaller diameter and the seal ring acts as a conventional seal. However, due to the smaller seal groove diameter, the piston will contact the bore when side-loaded resulting in scuffing, wear and leakage of clutch apply pressure.
Each piston in the Sonnax accumulator piston kit 44894-01MK features two guide seal rings, one at each end of the piston to prevent piston-to-bore scuffing when side loaded. Additionally, the oil sealing ring location is relocated on the piston allowing it to run in an un-worn portion of the bore enabling bores with moderate scuffing to be salvaged. Manufactured from 6061 billet aluminum, these pistons will upgrade late model applications with plastic pistons to prevent transmission failure due to piston breakage.
See instructions for details on allowable bore wear.