Just figured I'd throw this out to anyone who MIGHT have some shifting problems with the AX-15.
Quick bit of info. Purchased out 89 YJ with a transplanted 4.2, AX-15 and a Chrysler 8.25 rear end along with some other mods such as a lift etc. Anyway, we bought it knowing it was having shifting problems and assumed it needed new syncro's as it was not happy going between gears w/o matching rpms.
Well after a long cold winter and cleaning up some wiring issues etc I decided it was time to pull the trans and get it rebuilt. When I pulled the shifter out I discovered it was FULL to the very top with fluid.
So I pulled the FILL plug and about 3.5 quarts of lube came out. I put the fill plug back in for a run around the block and now it shifts about 80% better.
Keep your fingers crossed that no other damage was done by the P.O. A complete drain and fill with Redline will hopefully cure the other 20% of it's issues.