6L80 Transmission Fluid Thermal Bypass Valve Add another measure of protection and increase fluid flow to transmission cooler. Increase cooling capacity with this easy-to-install billet aluminum PPE Transmission Fluid Thermal Bypass Valve for the GM 6L80 6-Speed transmission. The OEM part has restrictive internal passages. When the OEM valve fails in the closed position, transmission fluid doesn’t reach your cooler. This can be caused by mechanical failure or debris. The result of stock valve failure can cause the transmission to dangerously overheat. Without properly cooled transmission fluid, the demands of towing and rigorous stop-and-go driving conditions shorten the life of transmission components. The PPE Bypass Valve eliminates the extremely restrictive mechanical factory valve, maximizing fluid flow to and from the transmission cooler. For further protection, a Neodymium magnet equipped service plug with O-ring seal has been added. The removable plug traps ferrous debris and can be accessed to remove particles from the system. The factory bypass valve does not have this feature. Check for Compatibility! Vehicles equipped with quick connect fittings and clip-style trans line retainers are not compatible with PPE p/n 125068000 6L80 Thermal Bypass valve. Vehicles equipped with the plate and bolt-style trans line retainer is compatible with PPE p/n 125068000 6L80 Thermal Bypass Valve.