Vibration/Rattling coming from Transfer Case

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

UPDATE: I've narrowed down my issue to the transfer case. Upon startup, it makes a rattling noise akin to something caught in a garbage disposal. This is definitely coming from the transfer case as I listened to it with a mechanic's stethoscope while it was on a lift.

The transfer case fluid was drained and came out BLACK with metal particles. It was then filled with new fluid.

4HI and 4LO engage just fine and work just fine as well. The vibrations are pretty constant but worse around 60mph and are felt in the gas pedal and driver's side floorboards.

The CV boot on my my front drive shaft where it connects to the transfer case is torn and gritty, so I will be replacing the head this weekend.

I was able to remove all the bolts holding the front drive shaft in place, but it just won't budge. I cannot get it out for the life of me. I've tapped lightly with a hammer, sprayed it with PB blaster, and yanked and tugged to no avail. Unfortunately if I can't get it out I will have to take it to another shop just so they can pull it out. I'm really hoping I don't have to do this.

If anyone has any idea what the issue with the transfer case may be, or has suggestions on how to loosen the front drive shaft to remove it after removing all the bolts.. I'd really appreciate some advice.

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I recently installed a full OME lift and new 245/75r16 tires and now have a slight pulsating vibration at 55mph and higher. The drivers side floorboard vibrates as does the gas pedal, but not the steering wheel or seat.

The tires balanced out fine and I had an alignment done as soon as the lift was on. U-joints are caked in rust but seem solid enough. Am going to rotate the front tires to the back just to be sure it's not a balancing issue.

Anyone else experience this strange pulsating vibration and/or have an idea of how to fix it?

spitfire36o · **Posted:** Tue Sep 25, 2012 8:29 am

How many miles are on the U Joints? The added weight of the tires spinning may have made the worn joints more noticeable. Additionally, check your ball joints, sway bar links, and control arm bushings for play.

BugginKJ · **Joined:** Mon Jul 06, 2009 7:35 pm **Posts:** 4576

If the vibration occured AFTER the lift I would say make sure everything is torqued down properly and the rims are mounted squarely to the hubs, especially if they are aluminum rims.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

The KJ itself has 116,250 miles on it. I bought it with 85k, and have yet to replace the U-joints. I'm not sure if the previous owner ever replaced them, but judging by the looks of them... they didn't.

The rims are steel Soft 8's.

When checking for play, does the front end need to be off the ground? Or could I check while it's parked on a flat surface?

tommudd · **Posted:** Tue Sep 25, 2012 9:54 am

Drive down the road 5 miles or so, pull back in the drive way and then put your hand close to the u-joints, if they are bad they'll feel hot/warm to the touch
U-Joints rust inside the cap, you now have them rotating on a different plane , they were OK before but now being rusted they are trying to change angles and can't
Just looking at them does nothing
4 or 5 of the ones that were lifted here did the same thing afterwards
Also check the rear boot on the front driveshaft to make sure it's OK while you are under there

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Thanks Tom. I'll go for a spin on my lunch break and then check on the U-joints and the boot. In terms of the boot, what am I looking for? Tears?

Keeping my fingers crossed that the U-joints are my issue, since that'd be an easy fix. If so, I'll definitely upgrade to the greasable joints.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Didn't feel like waiting until lunch so I took it out for about 5 miles and the u joints aren't hot at all. Any other way to check them?

tjkj2002 · **Posted:** Tue Sep 25, 2012 10:59 am

Elmer wrote:

Didn't feel like waiting until lunch so I took it out for about 5 miles and the u joints aren't hot at all. Any other way to check them?

Yeah,pull the rear driveshaft and then you can feel the movement in the joints better and spot a bad one right away.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Good point. I'll have to do that this weekend.

With my parking break on and in neutral, the rear drive shaft has about an inch of rotational play. Is this normal or might this be the issue?

Taking off OD when the vibration is present doesn't get rid of it, but does dampen it a bit. Letting off the gas also doesn't get rid of it.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Well, I drove around for another 15 minutes or so at 55+mph and now I do feel that the front U-joint is considerably warmer to the touch than the rear u-joint. It's not hot enough to burn me or anything, but the front joint is absolutely hotter than the rear.

tjkj2002 · **Posted:** Tue Sep 25, 2012 2:05 pm

Elmer wrote:

Well, I drove around for another 15 minutes or so at 55+mph and now I do feel that the front U-joint is considerably warmer to the touch than the rear u-joint. It's not hot enough to burn me or anything, but the front joint is absolutely hotter than the rear.

It's not uncommon for higher mileage KJ's to experiance rear driveshaft u-joint failures and front CV axle failures after being lifted,or uncommon on any vehicle.Those joints may have been okay at the designed angles but go south right away when there normal operating angle is pushed to the extreme limit of it's intended operating angles.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Definitely makes sense. I'm going to attempt the u joint replacement on my own next time I visit my parents as I live in an apartment and don't have a good assortment of tools. I'd at least like to have a bench vice.

Do you guys recommend the greaseable u joints? They can be greased rather easily right? Any specific brand or part number i should go with?

Thanks again for all the help.

tjkj2002 · **Posted:** Tue Sep 25, 2012 3:11 pm

The greaseable vs sealed u-joint is a great debate.

Greaseable's are weaker by design and actually require to be greased often(every oil change) or they will fail early.Sealed u-joints are stronger and if the seals remain intact should run in a stock configuration for 100k+ miles,less if lifted but all u-joints will not last as long as they should in a lifted vehicle.

The only u-joint brand I would ever recommend is Spicer u-joints,all other suck for a driveshaft apps.Solid front axle u-joints is another story but Spicers are still the prefered unless you got the coin for the good joints that are not DD freindly.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Sounds like I should go with sealed Spicer joints for the time being. Once I buy a house and have a garage I will make the switch to greaseable.

Thanks for the info man.

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Here are some pictures of my rear driveshaft. I read that the KJ will automatically adjust the pinion angle when you lift it, but it doesn't look like mine has done that. Am I correct in this statement?

Does this indicate that my U-joints are seized?

tommudd · **Posted:** Thu Sep 27, 2012 3:03 pm

mmmm not seeing any pictures ??

Automatically adjust the pinion angle? Where did you read that ?

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Pictures should be showing now. Had the album set to private by accident.

Read the part about adjusting the pinion angle here: http://www.jeepkj.com/forum/f203/adjust ... gle-49439/

Quote:

The 4 link rear on a KJ requires no pinion angle adjustment when lifting as it will adjust itself with OE arms back there.Big difference comparing a Fords rear leak springs to the KJ's coils and linked suspension is apples to ornages.

If this is the case, and my U-joints are rusted and seized, replacing them should allow the pinion to adjust to the correct angle, right?

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

Can you guys see the pictures now?

tommudd · **Posted:** Fri Sep 28, 2012 3:02 pm

Can see the pictures and see nothing wrong. Worrying about something that is nothing really
Check the rear u-joints and replace :wink:

Elmer · **Joined:** Sat Sep 22, 2012 11:43 am **Posts:** 83

tommudd wrote:

Can see the pictures and see nothing wrong. Worrying about something that is nothing really
Check the rear u-joints and replace :wink:

You the man T mudd. Replacing both driveshaft u-joints tomorrow and will report back.

Vibration/Rattling coming from Transfer Case

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