Ford sells 2 different versions of the traction lock for the 8.8 rear, one for 28 spline and one for 31 spline axles. Does anyone know if the inside spider gears are the same other than the splines, as in could you just swap the 31 spline spider gears into a 28 spline traction lock? The reason for this would be to step up to some 31 spline moser axles.

 

To my knowledge, You should be able to swap the axle gears from 31-spline into 28-spline carrier (providing You are swapping OEM to OEM carrier & L/S to L/S or open to open carrier).

What You will need to examine closely: make sure the 28-spline carrier is bored large enough diameter to accomodiate the larger dia. 31-spline axle shaft to pass thru 28-spline carrier. If old carrier is not large enough (where 31-spline axle shaft goes into carrier), You will need to remove carrier from differential housing and bore or drill to approximately 1.505".

The above also applies for 9" ford differentials too.

 

Thanks, Someone else was telling me that too, that the pin is a different size.

 

Early 8.8" diff. (pre. 1983-1984 ??) had a 3/4" spider pin. Late 8.8" diff. has a 7/8" diameter spider pin.

Internals for early 8.8" will not interchange with late-style internals. Early v/s late style internals on 8.8" diff. have different tooth pitch on internal gears and will not interchange with late style internal gears.

 

Early-style internal kit and bare carrier (which has 3/4" spider) is N.L.A. If you need service parts for 8.8" carrier that has 3/4" spider pin--you will need to search used or update to new carrier, which has 7/8" dia. spider pin.

This is true for open and L/S.