Was the AX15 installed on Toyotas? I thought I read that somewhere. However, if it did come on a Toylet, the bellhousing would not fit a 4.0. The BA10 BH won't fit to an AX15, either.
So, that leads back to an XJ or YJ.
Two years ago, there were two XJs in a local LKQ with AX15s. One was a 4wd with an internal slave cyl. bellhousing; the other was a 2wd with an external slave cyl. BH. I left there with a 4wd and a BH for external slave cyl. Long day.