4L60 4L60E 4L65E 4L70E Transmission Heavy Duty 2-3 Shift Valve Drop-In Replacement Extends life of the forward clutch & Input sprag The Sonnax valve applies the overrrun clutch in D3, 1st, 2nd and 3rd gears for added durability, where the OE valve applies the overrun clutch only in D3, 3rd gear. This valve also works well with aftermarket electronic "paddle" shifters to allow full downshift engine braking in 2nd while the shifter remains in the D3 position.