Quote Originally Posted by Rumpelstiltskin View Post
A gear driven Transfer case would take the abuse and would be strong enough, chain drive will have issues and oil problems.
I honestly would look into custom gear boxes, and redirect power units.
I wish I could offer more help, but I think you will be opening a can of worms trying to convert a transfer case.
I agree. Atlas apparently makes a gear driven TC that is built to stand up to 700 ft/lbs or better. However, would have to see how they configure the output shaft bearings etc. Probably not intended for full time front drive only.

Quote Originally Posted by arveetek View Post
Very cool idea!

However, I'm afraid that the front diff from a 1 ton truck would not be strong enough for full time use lugging around a motorhome. The front diffs were never intended to be used for full power, only when split between the rear and front diffs for part time use. Think of it this way: in a 4WD 3500 truck application, the rear diff would usually have a 10.5" to 11.5" ring gear, while the front diff would only have a 9 to 9.5".

Having said that, I'm not sure what size the original Toronado "ring gear" is, but chances are, whichever engine you swap in will have more power output than the original motor had, so it would probably need a beefier drivetrain anyway....

What's so bad with the Toronado setup anyway? My dad is actually using that TH425 tranny/transaxle in a project he's currently building: a 1964 Corvair that will be converted to a mid-engine Chevy 350.

Casey
Not too concerned about the diff. My "B" and "D" body cars had 9.5 diffs and I have seen them built to significant specs. The 1/2 shafts on the 3500 are beefier and the output shafts also seem to be heavier.

My issue with the original setup is that the newest 425 available would still be over 35 years old, plus does not play well with the newer engines. Loved the older torgue monsters (the original Olds Toronado 455 was rated for over 500 ft/lbs.) but again they are also over 40 years old.

The reason I want to go with the swap over to the 3500 subframe is to allow me to go with newer powertrains and more substantial suspension bits. Just going with the newer unit front wheel bearings is reason enough. Better brakes, heavier torsion bars, etc. make for a better setup. The original GMC motorhome weighed in at 12,500 lbs. I assume I will be adding another 1,500 to 2,000 lbs with my modes. Well within the specs of a 3500.

I am going for reliability here and the ability to get it fixed when on the road. Finding a good used 425 in a junkyard while 2,000 miles from home is not my idea of a good time.

Thanks for the input. Finding the right transfer case is still my primary concern.

Bill