Front half shaft *Updated with Pics *Updated again

wildrussian · **Posted:** Mon Oct 29, 2007 10:00 am

So Im still working on trying to figure out why Im getting humming and vibration between 40-50 mph. It never used to do that before the Rustys lift and I still have stock tires, so its not that. I have 2 ring clevis in the front and no extra isolators in the rear. I was thinking that it could be the front half shafts CV joints but the angles don't look that extreme at all. Could I have pulled out a half shaft on accident while putting in the lift that would make it vibrate and humm at 40mph? Any other ideas?
Thanks

tommudd · **Posted:** Mon Oct 29, 2007 10:12 am

did you get an alignment right away after the install? If not maybe tires feathered a little, have you tried rotating them to see if it still does it? Check the rear u joints as well, replaced mine two weeks after I installed the lift, think they were going bad before but with the increased pinion angle it finished them off.

myjeepwalks · **Posted:** Mon Oct 29, 2007 10:34 am

Quote:

Check the rear u joints as well, replaced mine two weeks after I installed the lift, think they were going bad before but with the increased pinion angle it finished them off.

Yes check the rear ujoints. I now get a nasty viberation on hard acceleration from my bad ujoints. They are starting to give the rotational squeak also.

wildrussian · **Posted:** Mon Oct 29, 2007 11:12 am

tommudd wrote:

did you get an alignment right away after the install? If not maybe tires feathered a little, have you tried rotating them to see if it still does it? Check the rear u joints as well, replaced mine two weeks after I installed the lift, think they were going bad before but with the increased pinion angle it finished them off.

Yeah I got an alignment since then and tire rotation and balance. whats the best way to tell if the U-Joints are bad?

tommudd · **Posted:** Mon Oct 29, 2007 11:29 am

well most times they will get loose, you can actually grab the driveshaft and shake it BUT.... then mine just froze up, I thought thats what it was but climbed under after jacking it up and it seemed fine, no wobble in the joint, took it for another drive and came back and when I grabbed the rear joint and it was hot as ... :wink:

heck, changed them out no more bad vibes etc.

wildrussian · **Posted:** Mon Oct 29, 2007 11:46 am

You know if its is u-joint indeed, since it satrted vibrating and humming after the lift, would the same thing not happen with the new U-joints?

tommudd · **Posted:** Mon Oct 29, 2007 12:39 pm

In my case I think they were starting to go bad before the lift but then when I changed the angles it just really compounded the issue.
But I know it will cause a vibration that is hard to trace in a way. I just wish all those things ( ujoints/ ball joints etc. ) still came from the factory so you could grease them!

wildrussian · **Posted:** Mon Oct 29, 2007 12:46 pm

yeah I know! Well I just got under it and checked the rear driveshaft and it seems like all the u-joint in there are nice and tight. You know I drove it again to get a better feel for it and Im getting more noise than vibe. I can't really describe it but it feels like its coming from the front end. I also want to say it started being more noticebale after the alignment. Im going to try to take the front drive shaft off and see if that fixes it.

wildrussian · **Posted:** Mon Oct 29, 2007 7:06 pm

Here are some pictures I took after I got home. Let me know if something doesn't look right.

Passenger Half shaft (axel)

CV Angles

Front Driveshaft Angles

Closeup of Front Driveshaft t-case side

I tried taking the front driveshaft off to see if it helps with the humming noise but I couldn't get my wrench to the top bolts on transfer case side. Any tips on removing the driveshaft?[/img]

tjkj2002 · **Posted:** Mon Oct 29, 2007 7:14 pm

Quote:

I tried taking the front driveshaft off to see if it helps with the humming noise but I couldn't get my wrench to the top bolts on transfer case side. Any tips on removing the driveshaft?

After you get the bottom bolts out either drive your KJ a little forward to pot the top bolt on the bottom or jack up the front wheels and turn the shaft untill they are on the bottom.

corwyyn · **Posted:** Mon Oct 29, 2007 7:30 pm

tjkj2002 wrote:

Quote:

I tried taking the front driveshaft off to see if it helps with the humming noise but I couldn't get my wrench to the top bolts on transfer case side. Any tips on removing the driveshaft?

After you get the bottom bolts out either drive your KJ a little forward to pot the top bolt on the bottom or jack up the front wheels and turn the shaft untill they are on the bottom.

Thats what I did, jacked the front left just enough to get it off the ground, then just rotated it to bring the bolts around so I could get at them. Since I'm still open in both diffs I didn't have to get both tires off the ground. Also made it nice when I was tightening things up, I just held the tire to keep the shaft from turning and got all the bolts tightened down. And regardless of what the FSM said I had to undo the two exhaust flange bolts so I could pull the pipe down just a bit to get the shaft out.

wildrussian · **Posted:** Mon Oct 29, 2007 7:51 pm

Cool thanks, I will try to take it off tomorrorow and see if that stops the humming. Do the pictures look normal?

Jeepjeepster · **Posted:** Mon Oct 29, 2007 8:58 pm

wildrussian wrote:

Cool thanks, I will try to take it off tomorrorow and see if that stops the humming. Do the pictures look normal?

yes.

Dont forget to check the rear driveline.

kolesy · **Posted:** Mon Oct 29, 2007 10:54 pm

Man I am having the same EXACT problem as you are! I just started about 2 weeks ago. I can not figure it out for the life of me! I have been under the rig too many times to count and everrything seems fine and solid. No slop anywhere and everything seems in place. I just can't figure it out! I even took it to the stealership to have them look at it and the guy said it was my tires out of balnce! "did you know all the weights they have on the inside of your rims!!??" Of course they are steeelies and I don;t want the weights on the lip of the rim! But anyways......

I was thinkin, could the grease in the cv joints have dried up and the joints are wearin out? Would this cause the vibes?

wildrussian · **Posted:** Tue Oct 30, 2007 6:05 am

kolesy wrote:

Man I am having the same EXACT problem as you are! I just started about 2 weeks ago. I can not figure it out for the life of me! I have been under the rig too many times to count and everrything seems fine and solid. No slop anywhere and everything seems in place. I just can't figure it out! I even took it to the stealership to have them look at it and the guy said it was my tires out of balnce! "did you know all the weights they have on the inside of your rims!!??" Of course they are steeelies and I don;t want the weights on the lip of the rim! But anyways......

I was thinkin, could the grease in the cv joints have dried up and the joints are wearin out? Would this cause the vibes?

Me and you both, I will try to take my front driveshaft off this weekend and see what happens. Let me know if you get this figured out before I do. I don't know if the greese would dry out if you don't have a puncture in the CV boot. Did you check them everywhere?

kolesy · **Posted:** Tue Oct 30, 2007 11:17 am

I checked what I could. Nothing found though. I can't really check the joints with out ripping the boots off. But I figure it is a possibility from water crossings and going through mud that the grease could dry out.

wildrussian · **Posted:** Tue Oct 30, 2007 2:59 pm

I was thinking and I have one more question about the driveshaft, seems like I started getting that rotational noise after I got the lift installed and if it is the front driveshaft that is causing the noise would it be worth it to even replace it? I mean if the lift caused the weird angles that made the shaft make noises if I replace it would it not do the same thing again even if its new? Any guys with the lift that replaced the front driveshaft please chime in.

raceinfan · **Posted:** Tue Oct 30, 2007 4:05 pm

sounds like you guy's are having the same noise & vibes that I'm having :?:

the vibes are realy noticable between 60-70 mph but NOT constint

the rotational noise only shows up when rolling to a stop/ light or gradualy taking off from a dead stop

I have the Rusty's lift also & clevis lift BUT I highly DOUBT that that is the problem alot of guy's are running the same set up & haven't had an issue

if you guy's find anything out let me know before I just go swapping all kinds of parts 1 at a time ( process of elimination)

tjkj2002 · **Posted:** Tue Oct 30, 2007 4:38 pm

wildrussian wrote:

I was thinking and I have one more question about the driveshaft, seems like I started getting that rotational noise after I got the lift installed and if it is the front driveshaft that is causing the noise would it be worth it to even replace it? I mean if the lift caused the weird angles that made the shaft make noises if I replace it would it not do the same thing again even if its new? Any guys with the lift that replaced the front driveshaft please chime in.

When you lift a KJ you do not change the front driveshaft angles,not any,zero degrees since the front diff is fixed in place.Now if you did a cradle drop then yes you will change the angles.

You do change the rear driveshaft angles though,and since our KJ's have sealed u-joints(non greaseable) then it is possible that they can go bad depending on how you offroad and take care of your KJ(ie washing the under carraige at least once a week) very fast,if you live in a area that uses salt in the winter they will go bad faster.

Also on the rear shaft is a vibration damper(like the one on the engines cranksahaft) that could be dry roiting and/or not balanced correctly anymore.The KJ "balls" that is on the rear diff is there to control rear driveline vibrations also.And don't forget that a weight on the F or R driveshaft could have come off also.

But since you are having rotanional noises I would check the front unit bearings,CV's,and front driveshaft CV's for any slop or binding.Don't forget that a little out of alignment can also cause some noises at certain speeds also.Then there is the possibility of the t-case causing the noises,it can happen,low fluid,stretched chain,worn bearings,worn oil pump,shift linkage not adjusted properly,and may need to grease the rear output splines.But don't forget about the front diff,worn bearings,low fluid,and such can cause the front diff to make noises also.

Though the first thing I would check is there anything rubbing(ie-calipers to rotors,rocks wedged somewhere against a rotating item).

USPLibby · **Joined:** Thu Jul 28, 2005 12:29 am **Posts:** 377

If you've never taken a look in the "tires" section of LOST then try reading all of our beefs pertaining to the stock tires. I am pretty sure that what you are hearing is the crappy Badyear SR-A's. I used to have to rotate my tires constantly to keep them quiet, minimum 3k or less. My stock tires used to start making a "wub wub wub wub" noise after only 1.5k miles. I think that they may have been slightly out of round also.

My Bridgestone Revos are pretty darn quiet for a AT tire and only started showing signs of feathing and noise after about 5k. I've actually only been rotating them about once every 6-10k.

Front half shaft Updated with Pics Updated again

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