Vibration problem after 2" lift - looking for ideas
This is in regards to my '01 XJ, 140,000 miles.
I installed a 2 inch lift last week. New springs, new shocks, along
with new ball joints, tie rod ends, drag link, sway bar disconnects
and track bar. Following the lift, I had the Cherokee aligned.
I now have a vibration. It starts at about 40 mph, is more noticeable
at 50mph, and is obvious at 60mph. Up to 75, the faster I go, the
worse the vibration. It does not diminish when I let off the gas.
The vibration is noticeable in my butt, through the soles of my feet,
and through the steering wheel.
ARB, and the company that sold me the lift, both said it sounded like
driveline vibration. Last night I installed a one inch transfer case
drop kit. The vibrations did not change.
My last idea was that a tire may be out of balance; perhaps I knocked
a weight off when I installed the lift. Also, some of the components
I replaced, especially the ball joints, were very worn. Perhaps the
vibrations were always present, and are now more noticeable.
Driving in 4-high either does not change the vibration, or reduces it
So I took it to a good front end shop today, and they test drove it.
They too thought it felt like it might be a tire. But three of the
four tire were exactly in balance, and the fourth tire was only 0.75
ounce off. Rebalancing that tire did not improve things.
There is no sign of tread separation. Before today, I last had the
tires balanced six months ago, and they were road force balanced at
The mechanic today also put it on the alignment rig, and confirmed all
measurements are in specification. He checked all universal joints,
and said they all seemed good.
He did notice that there is a fair amount of lateral play in the rear
bearing on the transfer case. His one idea is that there is enough
play that the driveshaft may be moving around and causing the
vibration. He isn't enthusiastic about this diagnosis, but it was his
I'm betting your pinion angle is not correct. Did you add shims with the TC drop? Mine is a 98, and I had a two inch lift and I had the same thing. on my current lift(3.5 inches) even with an SYE and new drive shaft, my pinion angle is still not correct (I put my shims in backwards).
I can feel no play in any of the four universal joints.
The short shafts that come out of the differentials (sorry, don't know the right term) have no apparent play relative to the differentials.
The shaft coming from the back of the transfer case has a noticeable amount of play relative to the transfer case. I can feel and hear a noticeable clunk from the case when I wiggle it up and down or side to side. No play in and out, though.
The shaft from the front of the transfer case has a little bit of play up and down, no play in or out.
The slip yoke (right term?) on the front driveshaft is noticeably loose. I don't know how to describe how loose it is, but there is a fair amount of play there, more than on the two output shafts from the transfer case.
I'll continue to update as I make observations and tests.
No, I just dropped the TC. As I said, the TC drop had no noticable effect.
Are you suggesting I shim the rear axle so the angle is the same as the dropped TC?
Yes, so that the axle slope is the same as or near(I dont' know the tolerances off hand), the pinion slope. FYI, I switched my shims around the right way (4 degree shims) and all my similar issues disappeared. It rides as smooth as a caddy on stilts. Seriously, if an SYE needs shims, a TC drop may as well.
I've owned my '99 since '00 and did a 3.5" lift then as well. A couple of years ago at just under 100K miles I felt all the U joints in the drive lines and they felt good. I decided they had served me well so I decided to replace them anyway. It's a good thing as some of the needles were rusty and dry and seized which masked any excessive play. Failure would have been eminent. I had the shafts rebalanced after I rebuilt them and everything works very well. I replaced the axle u joints, discs, pads and everything in the cooling system too. The old Jeep tracks perfectly straight with hands off the wheel at 80+ mph with BFG 31 KOs, runs cool in 100 degree weather with the AC on and is a pleasure to drive. I align it in the driveway using string and measuring tools.
No, I've always been under the impression that vibes were mostly from the rear drive shaft. Thats why some people try shims, to rotate the axle so that the pinion angle is changed.
But I really don't know then, hopefully someone else will chime and and let us know if lifting can cause issues with front driveline vibes.
Post-lift driveline vibs are usually from the rear drive shaft, but they can be from the front one as well. 2000-2001 XJs with the low-pinion D30 have more issues than earlier XJs with the HP D30, but angle-wise it generally isn't an issue until you get up in to the 5-6" lift range, and at that point you may also run into problems with bottoming out the double-cardan joint at full suspension droop.
However, if the slip yoke splines on the front DS are starting to wear out and there's some slop in it, that can cause vibrations as well (I've gone through two front driveshafts on my XJ due to worn out slip yokes, and it sounds like this is Ben's problem as well). Failing u-joints can cause vibs too if they get to the point of being sloppy.
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