Chrysler 9-1/2" LU converters have a high rate of failure due to the pressure spikes caused by the transmission, and reliable lockup pistons are hard to find. Sonnax offers piston plate CH-DA-3P, an improved design with increased wall thickness in critical areas, making for a stronger and more durable piston. This piston plate has a reactive surface finish like the OE piston, but is designed for a .045" thick friction ring instead of the OE .070" drop-in friction rings.
This piston does not include the damper spring retainers. The spring retainer must be salvaged from an OE piston assembly and welded to the new piston plate.