trackspeeder
Stone crusher.
Ford added the bypass to protect the tranny from damage. When the cooler lines plug up the rear section of the tranny will fail. Cause is lack of lube. Usually the output shaft bushing will spin in the case. Most cases are reparable with over sized bushings.
What the bypass does is open up when a restriction occurs. Rerouting fluid back to the tranny bypassing the coolers.
You can buy the bypass from Ford. Another option is a junkyard or tranny shop. If you go the used option, you can rebuild it with a kit from Sonnax.
Cooler line routing should be as follows. From the output port (front) to the radiator. From the radiator to the auxiliary cooler. From the auxiliary cooler to the input port (rear). Do not remove the rear fitting. This is a check valve. Its there to prevent drain back issues.
What the bypass does is open up when a restriction occurs. Rerouting fluid back to the tranny bypassing the coolers.
You can buy the bypass from Ford. Another option is a junkyard or tranny shop. If you go the used option, you can rebuild it with a kit from Sonnax.
Cooler line routing should be as follows. From the output port (front) to the radiator. From the radiator to the auxiliary cooler. From the auxiliary cooler to the input port (rear). Do not remove the rear fitting. This is a check valve. Its there to prevent drain back issues.