Recently, I've received a couple of requests for more information concerning a Duramax/Allison conversion in the 1990s 2 Wheel Drive (GMT400) body style trucks, asking whether the motor/engine mounts we offer would work. The answer is YES, but the transmission mount crossmember would need to be modified. Member Gordon Marks kindly sent me a couple images of his modified transmission crossmember, which explain how he accomplished his installation. Thanks Gordon!

Note: The factory 4WD GMT-400 (1990s) transmission crossmember works perfectly without modification in 4WD trucks. It appears the 2wd TRUCKS/SUVs have a somewhat different frame rail dimension when compared to the 4WD models. Mock-up the installation before committing to welding on the added material. You may find you need to adjust the height up/down a little to get ~ 3/4" clearance between the rear of the transmission and the transmission tunnel.

You can see from these photos that Gordon flipped the modified 2WD crossmember upside down and mounted it below the frame rails. Be sure to use lock-washers and thread locking compound just to be sure. Jim