Rear axle HELP

So as some of you already know the rear axle in my 1990 B2200 is howling so loud I can't even talk on the phone in my truck. I have a friend with a shop right up the road and he was gracious enough to give me a B2000/B2200 axle he's had laying in his shop for a couple years.
Now try to stay with me on this next part.
My axle or third member at least are stock '90 B2200. I know that from when I changed the pinion seal. Some how the previous owners changed the truck to 5 lug and I now know it wasn't a toyota axle swap. My axle also has an ABS speed sensor. The new axle has no speed sensor.
My plan is to just use the new third member in my axle housing so I don't have to redo all my 4 link brackets. So will this new axles third member swap straight into my housing?? Are they different with or without the ABS sensor or is that sensor the only difference between the two axles?? Also what oil should I run in the rear axle?? I've heard 80w90 but I'm not sure if their a better oil.
I'm hoping to swap this tomorrow so any advice or anything that might help would be great.
I just hate to get my axle tore apart and the new one not work.

maybe the axles came from an rx7?

as far as oil goes...i would run 75-140...its a good all around synthetic...i run it in my rear end and in my tranny.

The a me currently in my truck in for sure out of a 1990 B2200. It's the only pinion seal that would work. I know the new axle is a B2000 or 2200 axle also but it doesn't have a speed sensor like mine. I'm really hoping that's the only difference in the 2 axles.

Were the hubs redrilled? Pictures would help a lot here...

I just got it apart and someone has indeed redrilled the axle shafts and brake drums. It going to be really shitty when I need new brake drums. I've got this other third member I'm trying to put in right now so we'll see if it'll work.
When I pulled the drain plug on my current axle there was huge chunks of metal coming out but the ring and pinion look like their in good shape. There's just a ton of play in the pinion like the bearing is out. I cleaned all of the metal out of the axle housing so hopefully this will fix it.

Well the third member got rid of my howling noise. It's amazing how quiet the truck is now. After I got the third member in I started looking and figured out the axle I tore apart has the old first gen outer bearing lock nuts on the a or shaft so I'm guessing its a really old axle. But the third member dropped right in my newer abs sensor axle housing if that makes any sense to anyone lol. I really didn't think it was going to work after I got the first axle shaft out of the new axle and saw how old it was.
Now I have to try and fix a wheel bearing. The outer left one has a lot of slop in it I noticed when I put it so back together. I bet that's going to be a fun job. Anyone ever get one of these wheel bearings pulled off??