IFS?
The Hummvee has an IRS which is part of the reason it has good ground clearance. The problem with a live rear end is that the differential will always be at a constant height above the ground. A lift kit doesn't help - the body goes up but the diff. stays at that same constant height...
Pickup trucks are generally much lighter than the SUV built on the same chassis. My F-150 weighs 4200 lbs and the corresponding Expedition weighs 5100 lbs (!!!). Hence the F-150 gets far superior mileage. I'm getting 17-18 in town and 19-20 on the road. These are pretty good numbers for a full...