Transmission Bell Housing

When your drag racing vehicle is 11.49 or faster in the quarter mile, an SFI-rated bell housing assembly is required. This racing bellhousing requirement is in place to protect the driver and anyone around the vehicle, should the rotating clutch or torque converter fail and explode, sending fragments in all directions. In some cases a cover or scatter shield is required.

Without a transmission bellhousing, there isn't a way to connect the engine to the transmission case. The bell housing for transmission also creates the space between the two major components to allow either the torque converter or clutch assembly to fit within it.

A bellhousing is an automotive component or adapter that connects the engine to the transmission case. Bellhousings are typically made from aluminum and provide the correct spacing needed to allow room for the flexplate and torque converter (for automatic transmission applications), or the clutch and flywheel as well as hydraulic components (for manual gearbox transmissions). The bell housing function can also be designed to stop exploding parts from penetrating through it, which can injure the driver or others with exploding debris from the spinning components.

For most transmission bellhousings, cleaning is straightforward. Warm soapy water and a fine steel wool scour pad usually does a great job at cleaning aluminum. Brake parts cleaner works well in most applications at removing dirt, grease, and contaminants as well. For more stubborn stains, cleaning brushes provide a mechanical way of removing debris when chemicals alone will not complete the job. High-pressure water also is very helpful at cleaning bellhousings. Media blasting with walnut shells or other appropriate media is the best way to strip a bellhousing down completely.

There are a number of different sources that can cause a broken bell housing. One is due to the engine moving more than the transmission or vice-versa under heavy-load or high-horsepower conditions causing the bellhousing to be stressed more than its designed to. Incorrect part combinations such as the wrong starter or flywheel/flexplate that are not designed for the bellhousing can cause breakage as they introduce clearance or fitment issues. Incorrect tightening of bolts can cause cracked flanges from overtightening or a loose connection between the engine and transmission requiring bell housing replacement from under tightening. In some cases, a bellhousing can break due to poor quality of material or a bad casting of the housing.