Rolling both my questions into one post for ease of keeping everything easier to find!

Question 1: Answered in a previous post, but expanding on it here... Is it possible (or advisable?) to run the front XJ CV drive shaft in the rear position with a 4.5" lift, and if so, is that enough to overcome the rear drive line angle changes to eliminate vibrations? Would it still be advisable to run a TC drop or SYE with this, or just a TC Drop or SYE instead of the front shaft.

If I don't need to, I won't, as I already have a TC drop installed, with plans of doing a SYE in the future, but if I can and its a good idea, I'm all for it!

Secondly, on this question, are there any particular years I should be looking at to take the front CV shaft out of that will work on my 99 XJ? Or any years I should avoid, or certain vehicle specs from a donor XJ that I can't take the front shaft from? (Assuming per the original question this is even advisable)

Question 2: Found an 86 XJ Pioneer in the salvage yard with a OEM fuel tank skid plate and possibly a TC skid plate (Its sitting in tall grass, hard to see under the body), any problems bolting these up to my 99, or is the tank/TC different enough that it wouldn't be worth the modifying/fabricating to make it fit properly and functional.

 

You need a sye to use that driveshaft. And 86 is pretty different, I'm not sure how much you need to chop up to get stuff to fit... Tcase one will be easier to get to work.

 

I could be wrong, (and often am!), but I don't think the 86 fuel tank skidplate will fit on your 99 XJ.

Here's a rough pic of a skid from a 94 XJ (Metal tank)



And one from a 1999 XJ... (Plastic tank)



There's a lot of differences. The T-case skid might work, but I'm not sure. The transmission and transfer-cases are completely different in an 86 than they are in your 99. Different lengths, might be clocked differently...

HTH!