Unusual front end thump

meh_kick · **Posted:** Tue Apr 15, 2008 7:33 am

I've noticed an unusual thumping noise/feeling from the front of the KJ at moderate speeds (40 - 60mph). Also, while manuvering parking lots I hear/feel slight shutter.

How would you all recommend I troubleshoot? Hopefully it's just a tire out of balance, but I wouldn't be surprised if it's another driveline component.

Thanks.

KJ04 · **Posted:** Tue Apr 15, 2008 5:29 pm

meh_kick wrote:

I've noticed an unusual thumping noise/feeling from the front of the KJ at moderate speeds (40 - 60mph). Also, while manuvering parking lots I hear/feel slight shutter.

How would you all recommend I troubleshoot? Hopefully it's just a tire out of balance, but I wouldn't be surprised if it's another driveline component.

Thanks.

Might just need rebalanced, or possibly a bad belt in the tire.

Jeepjeepster · **Posted:** Tue Apr 15, 2008 6:29 pm

If you hear it in parking lots then its probably not a wheel off balanced.

If you think its a belt then rotate the tires and feel of the tread while youre doing it. I can usually feel a belt broken in a tire.

Do the usual checking of the suspension(Upper+lower balljoints, tierod ends, tie rods, rack, etc). Torque all the bolts and make sure the sway bar end links are nice and tight(100ft lbs). Ive had my end links loosen up twice now, you would think I would use alittle lock tite. :roll:

MNKK · **Posted:** Wed Apr 16, 2008 1:40 am

sounds familiar... could be bushings. I agree with above. check those areas. inspect the lil bushings. they get crushed easily.

psinsyd · **Posted:** Wed Apr 16, 2008 5:41 pm

Oh no, not another knocking thread. I'm suffering through the same thing (see the front ds slop thread)...Took out the front ds and it went away, put a brand new one in, and it's back! Ugh! I think now it's a CV, as it has now begun to make the nice clicking/grinding types of sounds.

I'm thinking about ordering Al's CVs along with new axle shaft bearings and seals. Not looking forward to how expensive this project is going to be to fix.
:roll:

Keep us posted.

meh_kick · **Posted:** Fri Apr 18, 2008 8:06 am

The noise has become more apparant this week - especially while driving straight at 45 - 50 mph. It also is still noticeable while driving in parking lots - though it sounds more like a faint grinding while driving slow that a thumping. I noticed another thing too - when I put the Jeep in 4wd, the noise pretty much goes away.

I'm not sure how to diagnose any worn components, but I am willing to work on it myself. I could use some help teaching me how to pinpoint the culprit.

Thanks again.

jimjeep0 · **Posted:** Sun Apr 20, 2008 12:46 am

I had something similar that ended up being the inner axle shaft on passenger side. The shaft's splines that the outer axle( with CV's) attaches to were shot. When jeep was on lift, you could grab the inner CV housing and move it around fairly easy. other side would baely budge. Replaced inner axle and CV axle as well as seal and beaing. Not a mechanic so forgive my terminology.
Good Luck

Rush345 · **Posted:** Sun Apr 20, 2008 1:54 am

Does it happen any differently when brakes are applied?? I have a warped rotor from a curb that ran out in front of me one icy night. When I even gently touch the brakes the steering wheel vibrates like crazy.

Jeepjeepster · **Posted:** Sun Apr 20, 2008 1:17 pm

If it goes away when its in 4wd then check the front drive-line and cv-joints.

I always thought those would get louder in 4wd though.

KJ04 · **Posted:** Sun Apr 20, 2008 2:30 pm

meh_kick wrote:

The noise has become more apparant this week - especially while driving straight at 45 - 50 mph. It also is still noticeable while driving in parking lots - though it sounds more like a faint grinding while driving slow that a thumping. I noticed another thing too - when I put the Jeep in 4wd, the noise pretty much goes away.

I'm not sure how to diagnose any worn components, but I am willing to work on it myself. I could use some help teaching me how to pinpoint the culprit.

Thanks again.

Just beat the he11 out of it the next time you wheel it, and whatever breaks will most likely be your problem.

meh_kick · **Posted:** Sun Apr 20, 2008 4:50 pm

KJ04 wrote:

meh_kick wrote:

The noise has become more apparant this week - especially while driving straight at 45 - 50 mph. It also is still noticeable while driving in parking lots - though it sounds more like a faint grinding while driving slow that a thumping. I noticed another thing too - when I put the Jeep in 4wd, the noise pretty much goes away.

I'm not sure how to diagnose any worn components, but I am willing to work on it myself. I could use some help teaching me how to pinpoint the culprit.

Thanks again.

Just beat the he11 out of it the next time you wheel it, and whatever breaks will most likely be your problem.

Maybe I'll try Sturgis after all... I'll make sure to have a spare front end before I do though. Hehe.

BeepBeepJeepJeep · **Posted:** Tue Apr 22, 2008 9:13 am

Just get under your truck and try and turn your front drive shaft by hand... if there's play, there's your problem.

Jeepjeepster · **Posted:** Tue Apr 22, 2008 10:10 am

There should be rotational play in both the front and rear drive-shaft. If it has any horizontal or vertical movement in the front shaft then there is a problem.

BeepBeepJeepJeep · **Posted:** Tue Apr 22, 2008 2:25 pm

Jeepjeepster wrote:

There should be rotational play in both the front and rear drive-shaft. If it has any horizontal or vertical movement in the front shaft then there is a problem.

I'm talking more so if there is play within the driveshaft... that is... the part after the CV joint spins freely from the part in front of the CV.

Jeepjeepster · **Posted:** Tue Apr 22, 2008 3:56 pm

BeepBeepJeepJeep wrote:

Jeepjeepster wrote:

There should be rotational play in both the front and rear drive-shaft. If it has any horizontal or vertical movement in the front shaft then there is a problem.

I'm talking more so if there is play within the driveshaft... that is... the part after the CV joint spins freely from the part in front of the CV.

understood.

meh_kick · **Posted:** Wed May 14, 2008 6:40 am

I found yesterday that the passenger side axle shaft is loose. When turning the passenger side front tire by hand, I can see the axle shaft wobble at the tube heading toward the diff.

My question now is how likely is it that I have a bad axle seal or bearing instead of an entire half shaft? How likely is it that other components (CVs, or diff gears) could have been damaged?

I'm driving to Colorado in less than a month and while I'd like to save some money on this repair to cover the cost of gasoline, I want to repair this correctly. One time only.

Your comments are appreciated.

Guest · **Posted:** Wed May 14, 2008 8:33 pm

Grab the axle itself, and push it forward and back and watch the boot. If the outer end of the boot doesn't move in relation to the front diff tube, but there IS play, you have a bad CV shaft. That make sense?

The Al's upper arms are longer, right? how MUCH longer? Any chance of a picture comparing the stockers to the Gen 4s or 5s?

jimjeep0 · **Posted:** Wed May 14, 2008 10:39 pm

re-read my prev. reply, I thought that was my prob. When we got it apart the splines on the inner sharft(inside tube) were shot. replaced shaft,seal. Also redid cv axle while apart( only another 125ish). Hope this helps,mine had gotten scary to drive. good luck

meh_kick · **Posted:** Thu May 15, 2008 11:39 am

jimjeep0 wrote:

re-read my prev. reply, I thought that was my prob. When we got it apart the splines on the inner sharft(inside tube) were shot. replaced shaft,seal. Also redid cv axle while apart( only another 125ish). Hope this helps,mine had gotten scary to drive. good luck

Thanks JimJeep. Where did you get your axles parts from?

jimjeep0 · **Posted:** Sat May 17, 2008 1:05 am

Not sure,
nothing special. It was all ordered fom a local parts supplier. I could try to find out if you need me to.
The guy that did it had the tools and know how, he let me help just because I bugged him alot.

Unusual front end thump

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