The bell housing is a bell-shaped aluminium part of the transmission and covers the flywheel and the clutch. It is bolted to the engine, near the starter motor, and its function is to connect the electric motor to a hydraulic pump. Some bell housings are made specifically for competition and have quick release bolts to allow the gearbox to be detached quickly without needing to remove from the engine.
If fitting a new bell housing, it’s important to ensure that it’s properly fitted and not misaligned. A misaligned bell housing can cause friction which can cause failure of the driveshaft, pressure plate or clutch which can all result in terminal damage to the vehicle’s transmission. Sometimes misalignment can be caused by the engine block that the bell housing is attached to and it may be necessary to replace the engine block.
Signs of a damaged or misaligned bell housing can be noticed through a grinding noise when the clutch is applied which is caused by the friction between the bell housing and the parts surrounding it. Friction can also cause the vehicle to drive slower than expected.