4L60E/4L65E Shift Kit & Valve Body Separator Plate Combo

This is the two-piece fix most shops end up buying separately: the Transgo SK4L60E reprogramming kit and the 46-PLT-96 heavy-duty tempered steel valve body separator plate, bundled with the valve body gasket. It covers 2001-2006 4L60E, 4L65E, 4L70E and 4L75E transmissions.

The stock separator plate on these units is thin and the 1-2 accumulator and TCC feed holes wear and wash out, which is where P1870 (transmission component slipping) comes from. The HD plate restores correct orifice sizing and the shift kit recalibrates line rise and accumulator timing so the 1-2 shift stops going light and the converter clutch stops slipping and burning.

Installation does not require pulling the transmission. Drop the pan and filter, unbolt the valve body, swap the separator plate and gasket, install the Transgo checkballs, springs and orificed parts per the instruction sheet, then torque the valve body back down and refill. Plan on a couple of hours on a lift with the unit in the vehicle.

Problems this addresses on high-mileage 4L60E family units: light or harsh 1-2 shift, no lockup or no 4th, converter shudder and burn-up, 3-4 clutch and 2nd band failure, rear planet and bushing burn-up, 1-2 bump and slide-bump, and the harmonic bounce that chews up pump and valve bores and causes shuttle shifting.