The bell housing alignment tool is designed to check for proper alignment between the crankshaft and the bell housing. Misalignment causes premature wear on clutch discs, pilot bushing, transmission bearings and may also cause transmission to jump out of gear. To use, simply mount the precision ground arbor to the crank shaft, then mount the bell housing to the block. Slide the aluminum alignment hub over the arbor and through the bell housing transmission alignment hole. If the hub goes through, the alignment is good. If the hub binds up, there is a misalignment problem that needs to be fixed. It is also recommended that the transmission mounting face of the bell housing be indicated true with the crankshaft. Includes arbor, hub, drill bit, alignment pin, alignment pin drill bit and arbor mounting bolts. "WARNING:This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm."