I am replacing my stock 28 spline axles and trac-loc with 31 spline axles and a corresponding 31 spline detroit locker. Do I also have to replace the stock pinion and get a 31 spline pinion?
I initially considered it but ran the numbers and decided against a 35 spline set up. One of the axle mfg sites (cannot remember which) had a calculator to help you decide what axle you needed. You would input your 1st gear ratio, amount of torque, and some other bit of data I am forgetting at the moment, and then multiply by .90. this gave you a figure of how much torque you would be subjecting your axles to. Then there was a chart showing how much the 28, 31, or 35 spline axles could take. I assumed a max amount of torque of 600 (adding a 150 shot of NOS to my set up) and got a number that was like 4000. The 31 spline axle had a 5000 rating and the the 35 spline axle was either 6 or 7000. I figured that anything over 31 was overkill for my application.