Rear Axle ????


Mar 28, 2005
I have an 87 GN question is I am switckhing to a PowerTrax set up an upgrading the axles. From what I compared I can replace my 28 spline with 30 splines an it wouldn't affect the carrier? Thanks Mike
powertrax is for converting an open to a psuedo posi (clunks on turns) more geared for low speed off roader trail trucks

you cant use 30 spline axles in a stock 28spline carrier that came in our 8.5" regals , you would need an open carrier from a 88 or newer 8.5" which have 30 spline axles from the factory

i would seriously reconsider the powertrax , they dont like being disengaged (when a wheel slips ) and then reengaging at high speed and high torque that we make

if you want posi go eaton posi which has 400# clutch pack get the 30spline unit with the appropriate install kit with larger diameter bore bearings and races (also called spool bearings) pop out your old peg leg carrier and swap the ring gear over , pop in the new eaton posi and the 30 spline axles will slide right in , and you wont clunk on turns
pinion angles ???

only thing to set when doing a posi install is the backlash by adding or subtracting shims to either side of the bearing races

if you were doing a gear swap then you would have to set pinion gear depth and then install ring to carrier and install carrier and set backlash and look at the gear contact of ring to pinion with paste to see how it looks. , but you dont need to mess with pinion at all for a carrier swap if reusing the original ring gear

if go with the 28 spline and you wont need to change the carrier or worry about shim as the powertrax can be installed with the open carrier still in the car , and you could use your original axles
Hey pacecarta, hate to bring this back from the dead, but do you happen to know the appropriate install kit for the Eaton 30 spline?