Shift Kit for 4L80E 4L85E Transmissions

The TransGo SK4L80E Shift Kit is a valve body repair kit engineered for 1991-2013 General Motors vehicles equipped with the 4L80E and 4L85E automatic transmissions. It targets prevalent complaints including soft 2-3 shifts, lack of upshifts, burnt direct clutches, and broken hard parts resulting from pressure issues. The kit features a redesigned, wide-land, self-cleaning boost valve and bushing that resist wear, ensuring consistent pressure regulation. It also includes an EPC boost pressure relief valve system to prevent excessive pressure that can lead to case or valve body damage. These components work with a slight increase in line pressure to enhance the transmission's overall durability and shift quality, providing short, smooth shifts. Key benefits and corrections provided by this kit include prevention of high-pressure parts breakage, reduction of soft 2-3 shifts, elimination of burnt direct clutches, and resolution of slow 3-2 downshifts and no upshifts. It also helps correct low-pressure issues stemming from solenoid filter breakup and addresses various diagnostic trouble codes. Installation notes indicate that transmission removal is not required for this kit. The kit includes a USA-made hardened boost valve and bushing, pressure regulator valve components, a new stronger 4th feed bolt, direct and reverse feed hole cup seals, a relief valve system, accumulator valve springs, and an actuator filter kit. TransGo also recommends their 4L80E actuator feed limit valve boring kit for all General Motors 4L80E rebuilds.