Quote Originally Posted by Yukon6.2 View Post
Hi Bill
I am sure that i read about someone using the Olds trans axle on a Dmax in the same motor home as you are looking for.
Might be worth some time searching the interwebs.
When I first started thinking about this, that was my first option. The 425 trans is essentially a turbo 400 with the torque convertor and the front pump split off the main body and a chain drive transferring power to the forward oriented main trans body and thus to the front diff (bolted onto the tailstock). Built like the proverbial brick outhouse but lacks things like a lockup convertor and maintains the original gearing of a 400. The first Toronados (1968) had the circuit built into them that used the dual range torque convertor (giving you effectively a 6 speed trans) and the newer 425 can be built to accept it but finding that convertor would be an issue.

A simple adapter to convert the BOP bellhousing to the Chevy bolt pattern is required plus modification is required for a different motor mount arrangement (single front mount with two mounts on the back of the trans) and a different flywheel to accept the 400 convertor. Don't know if the trans would hold up to a Duramax over the long haul plus as I mentioned before, you would be starting out with a 40 year old transmission with limited parts availability.

The age of the components that would have to be overhauled, plus the uniqueness of the various powertrain and suspension parts is what got me thinking of the 3500 subframe and modern parts to update what was actually a brilliant design for a motorhome.

Bill