Sonnax thrust washer GM-WP-16 replaces worn or damaged thrust washers in GM 6L90 Captive Clutch converters. Comprised of high-strength thermoplastic polymide (same material as OE), GM-WP-16 can also be used to add or replace the plastic thrust washer between the piston and turbine hub in GM 6L80, 6L90 (300mm) units.