Most converted EVs use a manual transmission for simplicity, and I decided that was the way to go. The first step was to find a suitable transmission, along with all the bits to make it work. I contacted Brett Quodling from Jeep City for some help, and he happened to have a very similar car that was originally a 2.5L diesel with a 5 speed NV3550 transmission. The deal was done, and Brett stripped all the other stuff out of the car and delivered the rolling shell to my door.
What I didn't expect was that this particular diesel engine used by Jeep is actually produced by VM Motori S.p.A. of Italy, and they supply many motor manufacturers. One side effect of this is that the part of the engine that mates up to the transmission bellhousing is actually removable. I am not sure if I will actually end up using this part, but even if I don't, it will make the job of making an engine plate quite a bit easier.