At work we have a few wheel chair vans that started out as 4WD diesel Ford E 350 vans. But the rear axle was removed to drop the rear floor, making it a FWD. Basically it is just the front half of the van with a fiberglass body added to the back.
Maybe the conversion wasn't done properly, but they are junk. Never mind the fact they ride like lumber wagons, they are just plain terrible. A computer system had to be installed to limit power because drivers would tromp on the throttle, and rip the CV joints out of them. So now they are gutless as hell, but somehow still have terrible torque steer.
I hear that the company that made them went out of business after being sued by the City of Toronto. They bought a whole fleet of them, and had nothing but problems as well.