I intended to put something together about this project but really have just been struggling to make time for everything I have going on. I will keep it brief and just provide some details of what we are doing to Josh's jeep, what parts were used, and any complications.
Josh's jeep is a 1991 YJ with the 2.5L and AX-5 transmission. He had been planning the swap and started having transmission issues so we tore into it. The drivetrain was removed leaving the factory wiring harness in the vehicle. The donor 4.0 was removed from a 1996 Jeep Grand Cherokee. The donor motor was in good shape with no leaks from the rear main, valve cover, or oil pan. An AX-15 from a 1997 TJ was purchased already rebuilt from East Coast Offroad and coupled to the 4.0 with a external slave bellhousing. Josh's 231 T-case already had a SYE installed but I had to tear it down to swap input shafts. I was able to salvage the input from a T-case repair I had done on a 2001 Dodge Ram 1500 a few months ago.
The first issue I had was needing the transmission mounting adapter for the AX-15. I sourced a broken one (common issue) from Neil and repaired it. I then duplicated it out of some 1/4" steel plate. This worked out perfectly.
The original motor mount provisions were cut from the frame and things were cleaned up. I slid the entire drivetrain in and mounted it to the skid plate. This allowed me to locate and tack weld the provisions to the frame. I then pulled the drivetrain back out and fully welded in the motor mounts.
We had to source another fuel rail as the YJ uses a return system and the Grand Cherokee that the donor came from was a returnless setup.
I will add some picture back in shortly. They are on my phone.