Sonnax Automatic Transmission Reverse Servo Spacers

The Sonnax automatic transmission reverse servo spacers provide a simple, low-cost way to add durability to the GM 4L80-E and 4L85-E transmissions and eliminates the need to retrofit early design reverse servo pistons into late units. Due to a design change in 1996, it had been found that the reverse servo piston commonly breaks because it is stressed more than early servos. Installation of Sonnax reverse servo spacers reduce piston stress by increasing the contact area between the aluminum piston and spacer and incorporating a cushion spring washer. The new contact area is over two times the original and the pressure between the piston and the spacer is reduced by 60 percent. The reverse servo spacer kits easily install during assembly and does not require machining or other modifications. Excessively high line pressure in 'Reverse' is directly related to boost valve wear and cross-leaks into the EPC oil circuit. For maximum durability, inspect and replace the boost valve with one of the Sonnax 4L80-E boost valve kits (sold separately). Product features and benefits: * Increased contact area reduces pressure between apply pin and piston by 60 percent * Added Belleville spring washer reduces shock on piston * No machining necessary, drop-in components * Maximum durability for minimal cost Show Less