Bell housing or bellhousing is a colloquial / slang term for the portion of the transmission that covers the flywheel and the clutch or torque converter of the transmission on vehicles powered by internal combustion engines . This housing is bolted to the engine block and derives its name from the bell-like shape that its internal components necessitate. The starter motor is usually mounted here, and engages with a ring gear on the flywheel. On the opposite end to the engine is usually bolted to the gearbox. The use of different bellhousings on a transmission allows the same transmission to be used on multiple engines in multiple applications. However, on some transmissions, the bellhousing is a nonremovable part of the transmission case. This is particularly true with front wheel drive transmissions, which are much shorter than conventional rear wheel drive transmissions.