Hey guys and gals. It's been a while since I've frequented the forum but I always seem to find good direction from you guys. Here's my situation..
I have a 91 2wd srw d350 that I am converting to a dually. I have a rear end from a 94 dodge 3500, 2wd cab and chassis model (d80?). The tube appear to be about 4" dia. What I'm curious to is what issues I may run into when swapping the rear end. I'm also wondering if there are off the shelf U-bolts and such that I can buy to attach the rear end with. Thanks in advance everyone! I appreciate it!

 

The drive axle code is found stamped on a flat surface on the axle tube, next to the differential housing, or on a tag secured by one of the differential housing cover bolts.
This code designates the axle ratio. I used to use Moser engineering for narrowing rear ends and axles I think they have U bolts.

 

Thanks. I'll have to check them out on u bolts.

 

I usually get ubolts bent up by a local spring shop, or order them from Rockauto.com. You gotta decide if you want to use square 2.5" ubolts or round 4" ubolts; and how long. Make sure they are at least 9/16", preferably 5/8" thread.

The Dana 80 has a longer pinion, so the driveshaft may need to be shortened. If you don't like that idea, you can use a something like this to move your axle back 1" or 1.5" on the leaf springs to compensate:

DIY 4x :: Suspension :: EZ Inch Kit

The 2ndgen leaf perches are 3" wide instead of 2.5". You may have grind them a little to make your ubolts fit.

 

Thanks for the info guys. It is most helpful. I do work in a machine shop as well so making parts isn't much an issue, I just want to get it right the first time. Thanks again!