88 E-350 pathdinder axle swap? D60 into a D61

I have a Dana 61 with Dana 60 guts: LSD and electric an locker. The Dana 61 is equally as strong as any 30 spline Dana 60. You can get any Dana 60 carriers/gear set or lockers, etc. to go into a 61; you just need the tallest deck height carrier, which is relative to the gear set ratio, plus a ring gear spacer....and before anyone asks. I have had a ring gear spacer in for years now and pushed alot of torque through it with no snapping crown bolts or any other problems. Putting Dana 60 stuff into a 61 is not straight forward, but achievable. You have to raise the pilot guide on the Dana 60 lockers, carriers, etc., which will enable you to install, and centralize, a thicker ring gear spacer. I had one custom made as there wasn't one thick enough on the market that enabled me to get my backlash down and within tolerance. Randy's Ring said it can't be done, but that, I think, was due to the lack of knowledge and experience in this type of modification. They were helpful in providing me with the deck hieght measurements thou. I think I have a picture of my Dana 60 Detroit Electrac before I installed it in my Dana 61 on the picture section. You can see I raised my pilot from 10mm to 25mm that enabled me to fit a thicker ring gear spacer . This had to be done on a lathe. I won't bore you with the details (email me if you want more info). In short, you can get any Dana 60 locker/LSD to fit in your 61. You just need access to a lathe or machine shop. Its not a curbside job for the weekend. Never heard of a Dana 59. One more thing, both Rob Mann and Gordon (Pathfinder) know what they're talking about! To my knowledge, the 61 was used in the early to mid 80's trucks and vans.

You should look for a late 80's like the one you own for a donor axle. Yes, you answered your own question as the 61 has a further pinion offset which is because of the high ratio gears, so stay away from those housings.

I think your best bet is to find a local driveline shop and have them install a new gearset. Dana 60 gears are everywhere and most shops are experienced with this axle.

You'll spend less money having a shop replace the pinion. If you buy a used axle you'll end up rebuilding it and spending more $$$, unless that's what you want to do anyway.

Aren't the rear axles on fod vans normally a Dana 61? They have a different Gear offset or something. Doesn't this prevent the use of my limited slip?

I checked the B.O.M. (bill of material) stamped on the axle tube and it indicates it's a Dana 60. I don't feel confident changing the ring & pinion, something about setting the correct backlash.