I have a factory 10 bolt rear axle 8.5 ring and pinon not normal 7.5 or what ever it is

I need to buy custom axle shafts and am trying to avoid taking them out to measure them so I don't have to spend the money for gear oil twice

my first question is does the 8.5 use the same axle shaft as a 7.5 because isn't one a 30 spline (8.5) and a 28 spline 7.5

im also re gearing the rear will any 8.5 master rebuild kit would work right all the same internals as like a Silverado 1500 10 bolt for example

 

i wanna say for us.8.5 is 30 spline,and about 28"

zr2 is 30 3/4"


Not sure on last question

 

The only thing the axle shafts have in common is the bolt pattern.

With an uncommon axle like you have, personally, I would pull both axle shafts and measure them to be sure of bearing diameters and lengths. There isn't a lot of info online about them, and maybe they aren't all the same... I hate wasting money on custom parts.

I think any 8.5 LD overhaul kit will work.

 

Thank you yea I'm pulling them today and going to buy new rnp and install kit