98 XJ lift question

Hey guys, just got my RC 3" aal lift on tonight and took it for a test drive..... noticed a slight vibration and you can kinda hear it through the floor.

Any ideas or advice..... Didnt think Id need an SYE and Driveshaft or I would have lifted it higher. It is my daily driver, should I not drive it as it is now? thanks

did you do a transfer case drop? first thing that comes to mind is this... spacers can be bought from tractor supply, youll just have to remove the studs in the frame (heat, some PB blaster, and double nutting usually works). if a T-case drop doesnt fix it, you may need a SYE.

another thing that comes to mine is u-joints. are they in good condition? i thought mine were, then only a few hundred miles after my lift they wallowed out bad. mine looked alright after a visual inspection, they might not be as good as you think. check for play in the shaft when its bolted to the vehicle.

id start by trying to identify excactly where the vibes are coming from. try a drop... go from there.

At 96 and newer the XJ's are prone to vibes after only 2'' of lift, because of the output shaft on the TC a 3/4'' TC drop should do the trick for you. I have heard of people with that much lift on those years still needing a SYE though.

There was actually a TSB for Non-lifted XJ's.I highly recommend a SYE kit(HD kit if you have a 231)!

Drive shaft is definitely the first place that you need to start. Worn out u-joints at stock height might not be noticeable until lifted when the driveshaft angle gets steeper. If they check out ok and you don't have a transfercase drop kit then get one but even if the u-joints are bad and you replace them, still get the t-case drop kit since it will reduce the vibes that you will most likely still get. After all this is done and you still have the same or some vibes then gets axle degree shims. These are shims placed between your leaf spring perches on the rear axle and the leaf springs themselves and they cause the axle to rotate slightly angling the axle pinion more inline with the output shaft of the t-case thus reducing the angles on the driveshaft more. These are fairly inexpensive attempts at curing the rear vibes compared to a SYE and CV driveshaft, however they are meant to help alleviate minor vibes but not harsh ones except the worn out u-joints since that can be a big problem. If none of these do it for you then you will need to go with the SYE and CV driveshaft. Some 96+ XJs get lucky with no vibes and some get it like crazy even with only 2 inches of lift. A slightly cheaper option for 96+ only XJs that need to go the CV driveshaft route is instead of a full SYE kit you can do what is called a hack-n-tap. Basically you remove the factory slip yoke from the rear output shaft and then cut the out put shaft short and drill and tap a hole in the dead center of the end of the shaft and then bolt on a solid yoke and use a CV driveshaft. This is a great cheaper alternative that will work but a SYE is still highly recommended over this since it beefs up the spline count of the output shaft over stock making the t-case stronger in a way for more abuse.

Just an idea, but instead of a transfer case drop, which just lowers the crossmember, couldn't you just run a shorter transmission mount? Daystar makes 3" (stock) and 1.5" poly transmission mounts. If he ran the 1.5" mount he could lower the transfer case 1.5" without lowering the crossmember.

No I haven't done the TC drop yet, It sounds easy enough to try. Basically trying to find the quickest easiest way to get this under countrol and then look for a more permanent fix....

VAhasnoWaves said I could buy spacers from Tractor Supply, could someone tell me exactly what I need and where to buy?? How much would help too. Do you think 3/4" or 1" or another size?


Also Im not exactly sure how to do this TC drop, I got uder there when I got home from work and sprayed PB on all four bolts of the TC crossmember... other than that I dont know what to do. Do I just put a spacer inbetween crossmember and TC and use same bolts to bolt it back up?

Also Im not exactly sure how to do this TC drop, I got uder there when I got home from work and sprayed PB on all four bolts of the TC crossmember... other than that I dont know what to do. Do I just put a spacer inbetween crossmember and TC and use same bolts to bolt it back up?

Yes you just need to space the crossmember away from the frame. I'd say 3/4" to 1" would be plenty. You may need to get longer bolts(cheap insurance IMO). If this doesn't solve your vibe problem I would try the degree shim method. Even after that you may still get vibe but I'd say with 3" lift you should be ok