Agree with Dave, dif setup is a science, but....

your keep Crown and pinion as a pair if you swap the crown from the welded dif onto the non welded carrier.

engagement patch is dictated by forwards backwards position of the pinion and side to side movement of the carrier.

your not moving the pinion so that variable isn't changing.

if you set the backlash the same your side to side position is the same so your contact patch is the same.

pinion bearing preload is something that a lot of people have trouble with, your not touching that so all good.

carrier bearing preload takes a bit of feel but is pretty intuitive if you've done wheel bearings.

have done this in trucks that do linehaul work as part of my day job.

Agreed with you Jon on all those points. 

I guess if you arent changing the pinion you are assuming it is correct, which i think on a 40yr old diff might not be the best idea. 

Though you sound more experienced than me. I cant stand the smell of gear oil, so i just pay diff shops money:P

Cheers for the info boys, I have a few more questions. Would different ways of welding the diff cause more difficult to pull apart? Also, different diff ratios would cause a problem correct? I'm pretty sure they're the same but it would be awkward if I pulled it all apart and they were different.

All the welded difs I've seen have the spider gears welded together and/or welded to the crownwheel carrier, neither of these should stop you unbolting the crownwheel off the carrier.

different dif ratios shouldn't hurt as you will be using the crownwheel and the pinion from the welded dif

Edited May 4, 20179 yr by Jon

2 hours ago, Jon said:

All the welded difs I've seen have the spider gears welded together and/or welded to the crownwheel carrier, neither of these should stop you unbolting the crownwheel off the carrier.

different dif ratios shouldn't hurt as you will be using the crownwheel and the pinion from the welded dif

Cheers Jon! I'l certainly have a look into pulling them apart. So basically just swap them over and be careful with lining up? 

Edited May 4, 20179 yr by SloRolla

This is how you weld diffs yeah?

 

on mine, that entire hole is just weld. It was pretty poorly done, slag all over the gears.