Checking Your Transmission Bellhousing For Cracks

Few amateur auto mechanics pay attention to the bellhousing of their transmission, but it's one of the most important parts. If your transmission is acting up, it's worth checking the bellhousing for cracks, understanding the typical cause of this problem, and how to fix it.

Finding Your Transmission

The first step in the process is finding your transmission, the location of which will vary depending on the type of car you drive. Rear wheel drive cars almost always have their transmission on the back of the engine, usually under the car near the center of the floorboard. You should see a drive shaft (a long cylinder) connecting it to the rear axle of your car.

On a front wheel drive car, you're most likely to find your transmission near the front-bottom on the driver's side, with a drive shaft connecting it to your front axle. These arrangements will vary by car, but a good tip for finding a transmission is to look for a drive shaft coming out of a small engine item.

Checking For Cracks

Once you've found your transmission, look for the bellhousing (the item covering most of the transmission) and visually inspect it for cracks. You should be able to spot any visible cracks in the surface quickly, but you should also run your hands over the bellhousing (while the engine is cool) to see if you can feel any finer cracks that the eye might miss.

If you feel any cracks, you have a problem here that goes beyond the bellhousing. Typically speaking, the bellhousing most commonly cracks due to poor alignment when it was installed on the transmission. Thankfully, you can check and even adjust this alignment to stop further cracks from spreading.

Adjusting The Alignment

Adjusting the alignment of your bellhousing requires removing the dowels that hold it to the transmission. These are large metal pins that you will see sliding directly into the bellhousing. Adjust the alignment by following this process;

  • Purchase a magnetic dial indicator and install it directly to the flywheel of the crankshaft by clamping it on
  • Turn the dial to drop the plunger until it touches the inside edge of the bellhousing
  • Check the automatic reading to find the misalignment amount
  • Purchase replacement dowels closet to the misalignment readout on your meter to off-set misalignment
  • Grab the original dowel pins with vice grips and pull them out
  • Lubricate new dowel pins with oil and carefully insert them in the holes create by the old dowel pins

Unfortunately, if correcting the alignment of your bellhousing didn't stop your cracks from spreading, you might need to get it replaced. Some transmission experts may be able to weld the cracks in your bellhousiing to save you replacement money, but it's often better to just start over from the beginning with a brand new bellhousing. To find out more, speak with a business like Atomic Transmissions. 


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