Sonnax heavy duty forward drum 34554-01 is a lightweight upgrade for GM TH400 high performance applications. Significant weight was removed behind the forward piston, leaving a larger fluid apply volume. This larger fluid apply volume does not significantly affect clutch apply and release times, but some sensitive applications may benefit from reduced volume with Sonnax clutch volume spacer kit 34554-11K. The optional spacer is manufactured from billet aluminum.

• Reduce clutch fill time when used with heavy duty forward drum 34554-01
• Billet aluminum spacer is lighter and more affordable than the OE steel it replaces