I am working on a cummins swap on my buddys truck and today we went and looked at a nv4500 at my freinds shop. The nv4500 is out of a 2 wheel drive gm flatbed with 50000 miles on it my freind will sell it for 500 to me. My question is will that work are the 2wd and 4wd trannys any differant from...