Originally Posted by bigriver
I'm not sure the difference actually. Really just want to eliminate what has shown itself as a weak point in my drive train.
A big difference is the lug pattern. Vans are 8x165 and the trucks are 8x170. Unless you can find an axle from pre-1999 I think. That's the year Ford introduced the Superduty. I could be wrong but prior to that the trucks were also 8x165. But ideally you want an axle with disc brakes. Ujoint specs the sterling which is 8x170 but check, maybe they have a D60 lying around.
The other issue is width or wms-wms. Lots of threads on this but with a FF out of an E series you will need wheel spacers to match the wms-wms on the front. Not sure if that applies to a Quigley but that's the dealio on a Sportsmobile 4x4 conversion. It's arguably the use of the spacers on a semi-float that leads to premature bearing and axle seal failure. Some have had luck finding a D70 out of a box van which is wider and there is no need for spacers.
If it were me I wouldn't worry to much about the gearing. If your sourcing one from a salvage yard with 100k you might want new innards anway. It's not that much more in parts and labor to change out.