Driveline vibrations from a bad u-joint or bent driveshaft can cause the Allison or ZF6 rear housing to crack resulting in expensive transmission damage. The repairs involved can cost up to $2,000. Reinforce the housing with Merchant Automotive’s Duramax Rear Housing and prevent damage to expensive parts. The brace can be installed in the driveway and it uses the factory bolts. This is an easy to upgrade for the do-it-yourselfer.