Rear end?
 

Are the axle housings from the Tacoma and 4runner the same? Next are the 4cyl and 6cyl the same. Mine is rotted bad in my 02 runner. So I'm curious thanks and yes I know I'll have to swap 3rds and prob axles

No, the tacoma's use leaf springs and the 4runners coils springs, so a taco housing won't have the spring perches. Other than that I believe they are the same, as long as you match up ABS/non-ABS, diff lock/no diff lock, etc.

4 and 6 I think the housings are the same, but the diff gears are slightly different (as in 4.10 on a 4cyl is slightly different than 4.10 on a 6cyl). IIRC the 4 cyl gear is slightly thinner. I think the rest of the diff is the same, so you could shim a 4cyl gear to go into a 6 cyl diff.

If you are just rotted out on the diff cover and not the structural part of the housing (which is likely), then you might consider weld repair. I replaced my entire housing, but if I had to go through it again now that I have even a cheap HF welder, I would probably try to make a new cover and just weld that on. It could be done for less than $50 in materials and I don't think it would be that difficult.

Ya found a tacoma rearend and noticed the differances. My whole axle is rotted lol

According to this web-site, the non-TRD rear Tacoma diffs are not the same, and not swappable to any 96+ 4runner. The Tacoma TRD diff could be swapped over, though.

http://home.4x4wire.com/erik/diffs/