Is the OD of 28 spline and the 26 spline the same?

I can't find any specs anywhere.

Aren't the side spider gears the only thing that dictates the number of splines the axles have? Or do the carriers and axle housings have different size openings for the two different spline counts?

I have a PowerTrax installed on 28 spline axles. The PowerTrax unit just replaces the spider gears with a locking mechanism. The problem is the rear end has 2.73 gears and I want 3.42.

I've found a rear out of an '85 v6, but it has 26 spline axles. Both rear ends are drum brake. All I want to do is slide the axles and PowerTrax out of the 2.73 rear end, and put them into this 3.42 rear end.

Will this work?

Here's a chart of what I know so far.

 

The OD is not the same. The 26-spline axle is sort of necked down just inside of the axle bearing race surface, the 28 remains thicker all the way to the center of the rear end. A 26-spline axle will slide right into a 28-spline carrier, but will just spin around in the gears.

I don't know what the size of the hole in the 26-spline carrier is, whether it's big enough to let the axle through; or whether the outer diameter and the bearing surface and all that of the 28-spline side gears is the same. It could be, but it doesn't necessarily have to be.

The inner diameter of the hole in a stock 28-spline posi carrier I have laying around is 1.2325". Measure a 26, and the axle diameter of a 28, and see if they'll go.

 

I tryed to put a 28 spline axle into a 26 spline 1986 carrier that had 28 spline side gears. The axle wouldn't fit through the hole. I drilled it out with a 1 1/16" drill bit.

The size of the actual splines are roughly all the same so the more splines you have, the larger the diameter of the axle needs to be to get enough splines around it.