Heavy Duty 2-3 Shift Valve4L60-E Sonnax has developed a drop-in replacement 2-3 shift valve that applies the overrun clutch in D3, 1st, 2nd and 3rd gears where the factory valve applies the overrun clutch only in D3, 3rd gear.
Applying the overrun clutch in 1st and 2nd provides added durability to the input sprag and forward clutch in heavy duty vehicles, plow trucks and high performance applications.
In addition, this upgrade works well with applications using aftermarket electronic paddle shifters. With the overrun clutch on, the Sonnax valve allows full downshift engine braking in 2nd, while the shifter remains in the D3 position.
No special tools requiredExtends life of the forward clutch and input spragIdeal for electrically downshifted units with aftermarket paddle shifters