TC question

Hello, first post
I am going to buy a 94 xj that has a 3" lift sitting on 31's but need TC replaced. I've never done anything as ambitious as this before. I don't know if it's a 231 or a 242 either. The guy says it won't go over 5 mph without a horrible grinding noise. Also says engine and tranny are good. Hope I'm not hitting off more than I can chew
Just wondering if anyone had some helpful tips and tricks to help me become more prepared for the job. Any pics of the removal/installation anything to help

I've been doing a lot of research on the XJ's and this forum seamed to have a lot of great info so I joined in hopes of learning even more
Thank you

You can identify the transfer case by the shifter.

Is it 2H 4H N 4L? If so, it is a 231.

The 242 has this:
two-wheel-drive, high (direct-drive)
four-wheel-drive, high (48/52 differential torque-biased-drive)
four-wheel-drive, high (locked, part-time)
neutral
four-wheel-drive, low (locked, reduction-drive)