I want to get a posi and see they sell both 26 and 28 spline units for the same price. Is it worth upgrading from 26 to 28 spline axles? I know 28 is stronger, but at what level does 26 become insufficent and warrant an upgrade?

Thanx!

 

if you're buying a 3series posi you don't have a choice because it will only work with 28 spline axels....i wouldn't want to think you would go out and buy a 2 series posi.

 

My 3 series Auburn is 26 spline. I run low 12's hi 11's but on 215/65/15 radails. I would not even think about trying slicks with this rearend.

 

When are the 26 spline shafts inadequate? You could argue that they are inadequate for a bone stock car. I've seen plenty of them break over the years. I've also seen plenty with 150,000 miles on them and no problems.

There are no hard and fast rules for driveline parts. People break so called stout parts all the time, and others run so called weak parts and rarely if ever break them.

I tend to ere on the side of caution. When I rebuilt my rear I upgraded to 28 splines. Did I need to? Would it have lived? I don't know, but the truth is that I didn't want to find out.