Newb question but none of my research has even mentioned this.... From what ive read 1st gen 4runners have 21 spline front axles. Many different upgrades to get away from the stock weak birfields. So lets say you wanna get a 27 or 30 spline longfield/marfield/etc. To me this would require a 27 or 30 spline inner axle and drive hub. Also i see an issue where the axle connects to the diff. Thats where im at right now, thanks.

 

Please do some more research.

85 4runner SFA is 30 spline at diff and the hub but necked down to 27 at the birf stock. 30 spline upgrade makes birf 30 spline too.

 

I think you're confusing the spline counts on tcases and axles.

As Wabbit mentioned, the solid axle is 30/27/30.

IFS has 27 splines at the hub

Tcases are generally 21 spline, except the turbo and V6 are 23 spline

 

now when you say that, it does sound like i was mixing the two. Thanks