I have a 1999 XJ limited with the NP 242. I was told by someone that a transfer case drop kit for these is different from the NP 231, and more expensive. My questions are 1.) Are they different? I'm ordering a lift kit with a transfer case drop in with the lift, and there are no questions asking which transfer case I have. They dont specify either one. 2.) I'm going with a 4.5 suspension lift. Will the tranfer case drop be ok with this much lift? It was fine on my wrangler, I've been told by a few it would be ok, but would like some more input before pulling the trigger. Thanks for any help. Much appreciated.

No difference. The drop is accomplished using spacers between the cross member and where it attaches to the unibody underneath. Same cross members are used for both TCs.

Cost difference is for Slip Yoke Eliminators. You will need to shim the rear end to get rid of driveline vibes along with either SYE or transfer case drop at that lift height. Ran a tcase drop on 5" of lift for a long time on a manual trans and it was fine.

I have a 4.5 " lift with transfer case drop, and still have just a tad of drive line vibration. Is this something that needs to be addressed immediately, or can I go a bit and save up for SYE kit? Should I stop driving it until then?

Your putting extra stress on the engine mounts and u-bolts in the driveshaft. Some people run no SYE for years with no issues. Some will go wheeling once and have a failure. My thoughts are its ok for normal street driving for a while, but the proper setup is the SYE. Save up and get one installed when you can.

Appreciate the input, thanks!