GM 8L90 captive clutch assemblies are difficult to rebuild and are prone to shudder. Sonnax performance converter kits upgrade M5U 8L90 units with a stronger and easy-to-build multi-plate assembly. Featuring a fully machined, forged cover and piston, three high-thermal slipping friction elements and two clutch plates with low-wear splines, boost lock-up capacity without changing shift feel or controlled slip.
- #GM-RK-25 for M5U 8L90 units behind 4.3L and 5.3L engines
- #GM-RK-27 for M5U 8L90 units behind 6.2L engines
