TH350 TH350C Race; Outer; Intermediate Sprag; Heavy Duty Racing a GM TH350 and TH350C transmission puts huge stress on the OE intermediate overrun clutch outer race. Proven to deliver twice the torque capacity of any OE or other aftermarket race, Sonnax heavy duty intermediate overrun clutch outer race 35723HD-02 is a critical upgrade for unrivaled reliability at any power level.