I need help - this is driving me nuts...

Let me start by saying that I am not looking for free labor here, just hoping that someone with a trained eye/ear could help me diagnose a problem I'm having with the XJ. Yep, I'm still a noob when it comes to wheeling, and to Jeeps in general. Just thought I'd get that out of the way.
I've got a good low-speed thump coming from the front end, which turns in to a pretty decent vibration at high speed. The thump is audible from outside the vehicle. In addition to this, it seems there is an excess of "road feel" through the chassis at low speed - like you're able to feel the cracks and aggregate in the road a little too much. I'd just expect a little more cushion from the 33x12.5's on 15" rims. One of my two daily drivers rides on 19" rims and 35 series tires, it doesn't feel as harsh as my XJ. I'm willing to accept that some of the harshness could be from the Rusty's lift and the type of bushings/pivots used.
Schwab won't touch the Jeep due to the lift, nor will most of the other shops. I did have Schwab re-balance and check out the tires (Wrangler MTR's), and they found nothing wrong. I honestly thought a broken belt HAD to be the culprit.
My next assumption was that it could be a bent stub shaft, but it seems as though this would be difficult to detect during a simple visual inspection.
As far as payment - I'm willing to kick something down to anyone that could help - a few bucks, or a case of your favorite beer - or the return of a favor via deep discounting on some high-end gear for your house (plumbing, hardware, fixtures, etc... ). The later could work out massively in your favor...

Try this: Lift front tires off ground and try and move them top to bottom (there should be no movement) if there is its your bearing hub. Also, with the vehicle back on the ground, have someone look at the trac bar where it meets the "frame" as you turn the wheels left and right. There should be no movement up or down from the trac bar. I can see mine from outside the vehicle while turning the wheel but I have alot of trimming.
Check all steering connections (tie rod ends, ball joints, etc.) and get back to us.
Good luck!
Tim.

I understand your new to the jeep thing, but your description is a bit vague.

Based on what i've heard so far, a few things to check IMO would be,

Control arm bushings
Trac bar/bracket
Shock bushings

Wish i could help more, It sounds like one of the "Got to be there to understand" situations..

AXLE UJOINTS CHECK EM AND SEE IF THEY ARE RUSTED BAD, MINE THUMPS ALITTLE AT LOW SPEED, AND POPS WHILE DOING SLOW SHARP TURNS. CHECK THAT AND SEE IF THERES PLAY/RUSTED.

Xjcj3a said:

AXLE UJOINTS CHECK EM AND SEE IF THEY ARE RUSTED BAD, MINE THUMPS ALITTLE AT LOW SPEED, AND POPS WHILE DOING SLOW SHARP TURNS. CHECK THAT AND SEE IF THERES PLAY/RUSTED.

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could ya stop yelling at him.. :moon:

Well hell I'm late to say anything them are the same thins I would say to check out from what you have said it sounds like good luck let us know.

So where in NW Oregon would you be?

Mines having the same kinda problem! Mines like a rotational thump, gets faster the faster you go and slows down when you are slowing down! I was leaning towards my aussie being messed up but everything looks clean! I'm in the boondocks with no access to anyone that can help but when I figure it out ill let ya know! Does the thumping in yours get faster with speed?

I had the same symptoms with mine and it turned out to be a loose track bar bracket.

Los Lobos said:

So where in NW Oregon would you be?

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Wow, I let this one fall off the map - I appreciate the recommendations and suggestions. No wiggle, wobble, or run-out in the front end. Track bar bracket, though I still need to weld in some washers for reinforcement, is tight.
One thing I forgot to mention is that there is also a cyclic brake whistle - which coincides with the thump. That's what let me to believe that it may be a bent stub shaft - since the front brake rotors would wobble slightly in the caliper. I just bought all new brakes for the rig - I don't want to install them until I get this squared away.
How tough is it to replace the front axle shafts, stubs, bearings, etc? I've got nearly 130k on the odo, if I'm digging in to the front axle, I may as well freshen it up if it's not too involved (relative, I know).
I think I already mentioned that we ruled out the wheels and tires. That's the only part of my rig that Schwab would touch, lol.
I'm in Hillsboro.

88red2dr said:

Mines having the same kinda problem! Mines like a rotational thump, gets faster the faster you go and slows down when you are slowing down! I was leaning towards my aussie being messed up but everything looks clean! I'm in the boondocks with no access to anyone that can help but when I figure it out ill let ya know! Does the thumping in yours get faster with speed?

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Yeah. On the freeway, it's a higher-frequency shake.

Hey check all 3 of your mounts.

Check the U joints in the front DS as well. What type of lift are you running? On my 4.5" I was getting front D/S vibes due to excessive negative caster fromt the lift. Made all sorts of thumping noises.

I had the same issue with mine. If you have a 242 t case toss it into full time and go out on the road. if it clears up check the ujoints on the front drive shaft and at the wheels. Thats what was causing mine. also another thing that cleared up alittle more of the vibes was a beef'ier steering stabilizer, helped wonders.