I just pulled an NP231 T-case from a 1990 Jeep XJ and I am trying to swap that one into my 1994 XJ. There are no vacuum lines on my 94 and the 1990 231 has 4 vacuum lines that go into it near the tailhousing. What are these lines for? The 94 case also has different wiring than the 90 in that it has 2 wires in the front/top of the case and three wires next to the tailhousing in the back. The 1990 has only one wire assembly, which is next to it's vacuum lines near the tailhousing. I know that some of the wiring is for the indicator light, which I can do without, but I can't do without the speed sensor. Can anything be swapped like the tailhousing? If worst comes to worst I was thinking of just ripping both cases apart and swapping shafts, bearings, shift forks, and the chain. They are both 23 spline cases so I guess all of the parts should fit, right? I know this is complicated but any help here would be greatly appreciated as I am sort of in a jam. thanks!

The vacuum lines are for the vac-disconnect on the older D30's. The 2 wires at the front are for the indicator light, I think, and the 3 wires at the rear are for the speedo sensor. I'd just swap the hardware and keep your stock harnass entact, then plug your sensor into the new case. As for the vacuum lines, just plug 'em, you don't need 'em if you don't have a disconnect axle.