10 spline to 24 spline axle transition date?

[REDrum]

Is the transition year on SIIIs from 10 spline to 24 spline axles 1980? Or are there other factors besides mfg date? Assuming I have the original OEM rear diff, I am trying to determine if I have 10 or 24 spline rear axles. (BTW, truck is 4200 miles away otherwise I'd be wrenching to answer the question not posting..)

Thnx!

[albersj51]

I think the 24 spline came with the salisbury rear end only.

[jac04]

There was a transition to axles with 24 spline outers with 10 spline inners.

The transition was July 1980 on the 88" according to the LR parts manual. No other factors listed for 88" other than date.

[REDrum]

Thanks guys, looks like I'm going to have to find a 24 spline diff too...and that whole cost/performance decision point...