Sorry for the very late response, but I check in here maybe every couple of months now. Becoming a family man kinda changed things for me. <img src="/forums/images/graemlins/smile.gif" alt="" />

I think you're on track, and it sounds like the other guys have answered most of you questions. With my swap, I opted not to keep the Mitsu t-case because
1) it's very heavy and to do it properly another crossmember probably should be added
2) the cable shifter for the NP231 was ideal for keeping the shifter in the stock location as well as rigging up one shifter to control both t-cases
3) I didn't want slip yokes. If I had to remove a drive shaft for one reason or another, the t-case keeps it's fluid. Also it's easier to get a stout aftermarket drive shaft (I highly recommend Tom Woods for this, his shop was great in helping me out) and the u-joints, etc are available at any respectable parts store.

Sorry to break this into two posts, but I wanted to see what your engine and transmission was.

Like what was said above (which you probably understand by now) the easiest way to use these doublers is to swap the mitsu tailhousing (the casting that encloses the back of the transmission and provides the mounting surface for the t-case) with that from a newer model Jeep AW4 and modify the Jeep pulse ring. Also, very slight modifications to the transmission shift cable bracket need to be made, but that's pretty simple.

Toasty laid it out well that the clocking ring for the NP231 could be replaced with a custom adapter plate for the Mitsu case.

The electric speedometer can be very easy to adapt. My NP231 was a gear driven speedo output similar to what a mechanical speedo would have. I unthreaded the Jeep sensor from the housing, got an adapter square key from Autometer, and screwed the Mitsu sensor in place. The threads aren't a perfect match, but they are soooooooo close. <img src="/forums/images/graemlins/notooth.gif" alt="" />

Hope this helps, again, sorry for the late response. <img src="/forums/images/graemlins/cheers.gif" alt="" />

thanks mate, appreciate your reply.