Today i took out the AX15 out of they 91YJ. It doesn't have any identification numbers on it. It had one number on the top of it which is: 53005360. Do you know what that number means? Anyway i put the AX15 right next to the BA10 to see the size difference. They looked like the same length but the AX15 looked bigger (bulkier). For the most part they looked similar but i noticed some differences like some of the wire hook ups where at different locations but other than that they looked similar. The AX15 had about a 1 inch plate inbetween the transmission and the transfer case. And the BA10 was split down the middle length-wise just like you said. So all that confirms that i'm actually dealing with a BA10 and an AX15. Not that i didn't trust your info but i had to know for myself b/c for all i know the previous owner could have put another tranny in. Anyway, since both of them looked like they were the same length it looks like i shouldn't have a problem with the driveshafts not fitting.
Here's a couple of more questions for you. Do i need to take all the wires that hook up to the transmission/transfer case and swap them as well or should i be able to use the same wires on the different transmission and transfer case? I believe i have to swap out shift levers and transfer case levers and linkage and all. Is that correct? One more question, Do you think the cross-members in each vehicle will bolt right up to their new transmissions?
Sorry for all the questions, this is the first time i've ever done this. I've done alot of other work on cars but i've never messed with transmissions until now. I always like to learn by experience but i figured since i found this Jeep forum i might as well get a little knowledge to make things easier on me. I'll keep you posted on my progress. Thanks for everything.