Hi Guys, I just lifted my Jeep with a used RE 4.5'' Superflex Kit. I installed a t-case with an S.Y.E., have shims under my axle, got an alighnment and have all new bushings. My cherokee tracks straight down the road, and Im currently running my stock tires (until I can afford bigger ones) which were in balance before the lift. My problem is when I drive i have a weird vibration. The vibration speeds up as I speed up and slows doen when I slow down. I think that it is my front driveshaft ( I used the one that came off of the Jeep I stripped and not my original to the vehicle stock one). Any ideas? I figured that with the shims and SYE I shouldnt have too many driveline vibrations, as my driveshaft angles look good, I just feel as though the front could be the problem. Its not like a death wobble, or anything like that, but its really annoying and doesnt help for long drives.

 

take it to an alignment shop and have your caster checked

 

Your pinion angle might be too much with the lift for that CV shaft. Low pinion D30 correct? If so you have two options. One is to get a CV welded on the far end of the shaft. The other is to change the castor angle so the drive line is a straight shot to the pinion. However this also might cause you some death wobble. You will probably have to play with it. Personally, I would use a double cardan on both ends and call it good. If you do that, you will need to change the pinion yoke

 

Is your front slip yoke wore out? Is there a lot of play in it? Mine is hit. The thing vibrates terribly on the expressway. If I slip it in four wheel drive it mostly goes away.

 

hes most likely got a hp30 with a 99. not many late 99s were made wit lps

 

and it would definitely be a good idea to check your shaft slip joint. try pumping some grease in it.

 

i just went and swapped out my front driveshaft to a spare that i had. The one that was in my jeep was DEFINETLY worn out, Swapped the shafts, pumped some grease in, took it out for a ride and its much much better. Still a little vibration but not bad when compared. Thanks for the suggestions, ill keep you all updated if i decide to change anything else.