A cracked or hardened piston seal bleeds off apply pressure and the clutch it feeds slips under load.U540E bonded piston kit bonded pistons (7-pistons). The set covers the apply positions a rebuild opens.Return spring condition is part of the same circuit as the piston. The pistons are bonded rather than lip sealed. Shipping weight is 3.38 lb.The parts list below is exactly what ships. Compare it against your teardown before ordering.REMCO has supplied automatic transmission parts since 1991, and every order ships with its part listing so the receiving technician can check what arrived against what was ordered. Transmission Piston Kit for U540E - replacement component designed for proper fit and function Designed to support proper clutch apply pressure, stroke and sealing during piston and seal work Package Includes: one transmission piston kit as described, supplied loose for piston and seal work Bonded rubber lip seals on a steel or aluminum piston body - designed for dependable service in the intended application. Ships at 3.38 lb, 18x16x5 in Intended for builders correcting apply pressure loss. Lubricate the lip seals before assembly and seat the piston square in the bore