5R55W/5R55S TransGo Shift Kit Valve Body Rebuild Kit

The TransGo 5R55W/5R55S Shift Kit is a valve body reprogramming and repair kit for Ford's 5R55W and 5R55S five-speed automatics, the transmissions found behind 2002-up Explorer, Mountaineer, Ranger, Mustang, Thunderbird, Lincoln LS and Aviator. It targets the two failures these units are known for from the factory: a stuck or worn torque converter lockup valve that sets a P0741 code and kills lockup, and a slow or no engagement when the trans is cold.

The kit includes a new pump lockup valve assembly, EPC (electronic pressure control) relief valve assemblies, replacement valve body springs, and a pump alignment tool. Most of the parts drop into the valve body on the bench: you pull the valve body, replace the lockup valve and springs following the printed instructions, and reinstall. The pump valve that improves pump flow goes in the pump body, so if the converter is already out during a rebuild you can fit everything; on an in-vehicle valve-body job the rest of the kit still corrects the common lockup and pressure complaints.

Techs use this kit to recover a high-mileage 5R55W with a stuck lockup valve, to firm up lazy shifts, and to add line pressure margin so the clutches stop slipping. It is a reprogramming kit, not a full overhaul, so it pairs with a filter, gasket set, and fresh Mercon V or LV during a valve body service or rebuild.