Will an older 80's ring and pinion gear out of a toyata truck with 4 10s fit in a new 91 housing?? I know the older axle is skinnier but are the spline gears on the axles the same? And will the ring and pinion fit in the newer housing..

 

Off the top of my head I'm not sure. Search Toyota faq 2.0 on Google. Oodles of information and pictures. That's right, oodles.

 

Check out www.gearinstalls.com

 

Possibly yes, different pinion head thickness

 

swapping entire differential? should be a direct swap if late 80s model. if it was a 2wd donor, then NO.