This rear cover is a direct fit replacement for the factory rear cover, and has a modular Ford 4R100 bolt pattern. CNC machined from aluminum, this cover utilizes the factory gasket and rear main seal. The crankshaft position sensor, starter, and dipstick tube all bolt directly to it as intended from the factory. The cover comes with a gasket, rear main seal, and hardware for the 4R100. MADE IN THE USA.