Baystate Jeepers

Changing over my 87 yj poojunk 5sod trans to a 94 external slave cyl ax 15 can i still use my original rear drive shaft

Welcome to the forum.

The driveshaft may fit, and it may not. The BA10/5 and AX15 are similar in length, so probably. You'll just have to try it and see.
One question though, are you changing the transfer case to a 23 spline input? The BA10/5 has a 21 spline and the AX15 is 23.

I did the Peugeot to AX-15 swap on my 1989.
The rear driveshaft fit OK for me. Very little difference in the tranny length.
Ditto on the 23 spline input shaft requirement

Yep,
Went from BA-10 to an AX-15 to a NGS 6 speed. Never had an issue with driveshaft lenghs.

As Kurt and Joe pointed out, you'll need either a complete 23 spline t-case or a 23 spline input shaft for the t-case.

Also remember that you'll need a different pilot bearing/bushing in the crankshaft for the AX-15!!!!! The later AX-15 has a 3/4" dia snout vs. the BA's 5/8"

Yes im changing both they came as a complete unit is the 231 transfer case better than the 207 that was mated to the poojunk trans

Yes.

Thank you all . I lost the clip that holds the clutch fork to the bellhousing do i really need it if so where can i get one

You really should have it. Try a google search or try the dealer.

The clip part number is: 4338855
Only a couple of bux...