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Eldoradoman 10-05-2010 11:26 AM

Crazy vibration at hwy speed
 
Hey, did a search but haven't found the exact symptoms I have. Starting at 60mph I get a crazy vibration that feels like horribly unbalanced tires, then fades away around 75mph. Took front driveshaft off and it feels a little worse, rear u-joints don't seem to have any slop/play. I know my rear pinion bearing needs to be done but it couldn't cause vibration that bad could it?

It's not nearly as bad as death wobble but it's bad enough that I have to stay under 60. Rotated tires and it didn't changed anything either. Also, it's a bit worse under acceleration but only at those speeds.

Thx for any input!

NickMaloon 10-05-2010 01:32 PM

Sounds like a bearing problem, I've had that same problem with several different vehicles, if it only happens between those speeds, its likely to be bearings

Eldoradoman 10-05-2010 02:29 PM

Just checked the rear wheel bearings and they seem okay. I checked them like you do for the front by trying to rock the wheel left and right and up/down at 12 & 6.

Rotating the rear tires reveals my rotors are grooved a bit and the pads are slightly dragging but nothing obvious.
Is the rear pinion bearing more likely? How about an unbalanced rear driveshaft?

It feels more in the seat of the pants than the steering wheel.

edit: k i checked the front wheel bearings just to be sure and they seem fine. My pitman arm tie-rod end has a little play but it's been like that for a year now, just a little slop in the wheel. Balljoints seem okay too. My truck's front end was completely shot with a wheel bearing so bad it wobbled and it didn't vibrate like this jeep does.

Thx!

Eldoradoman 10-08-2010 04:28 AM

Any other thoughts?

gothchick 10-08-2010 08:24 AM

Could be a lot of things. In my case, it was the steering box. Got a new one and the wobble went away. I think KOR sells several different "wobble cure" kits or maybe it was csl offroad. Can't remember.

Unfortunately, you're just gonna have to start replacing stuff until you find the culprit by process of elimination... I replaced upper and lower ball joints, all bushings, new steering stabilizer, alignment, balance, etc, before finding out it was the steering box. But at least I have a new front end now. Lol.

Eldoradoman 10-09-2010 04:47 PM

The u-joint on the front driveshaft (diff side) keeps wearing out from the vibes also, and I just noticed a clunk when I rock it side to side coming from the driver's side shock/spring area. Come to think of it, it clunks when letting off the gas sometimes as the weight shifts.

I don't drive this Jeep but am trying to sell it so have just started getting to know it, will check all bushings and suspension-related bolts for tightness this week for starters.

Eldoradoman 10-23-2010 05:31 AM

Okay, so the vibes are definitely coming from the rear diff for sure, had it on a hoist running and can hear it all coming from the pot, mostly the passenger side. I popped the cover off and changed the fluid, old fluid was dark with just a couple sparkles but no signs of metal. Spider gears look good, couldn't tell if the pinion was worn but there are no chips or anything in the teeth.

My pinion bearing is worn out though, could it get bad enough to cause all these vibes?

How expensive is it to get just the pinion and pinion bearings/seal replaced?

Any thoughts?

newfieZJ 10-23-2010 08:03 AM

probably a toss up between the worn pinion bearing and a slight imbalance to the driveshaft .

It's about $4-500 to get the pinion bearings done in Edmonton per axle and about $100 to balance the driveshaft . My sure it's high RPM balanced .

Eldoradoman 10-23-2010 01:40 PM

So they're are two pinion bearings not just one?

The driveshaft didn't appear to be out of whack when it was running at hwy speed on the hoist, you think it could be subtle enough to still cause a vibration that goes through the whole vehicle? It does sound like it's coming from the rear diff inside, somewhat more in the passenger side axle tube.

I believe the pinion bearing is bad though (howls back there under throttle) so maybe it's worth getting it fixed.

Is there some kind of kit I can buy for the pinion bearings and where do I find it at a good price (in Canada)? I guess I need a new crush sleeve and pinion seal as well as the bearings, anything else?

Thx!

Eldoradoman 10-26-2010 07:08 PM

K, so my mechanic buddy said he'd do the pinion bearings for $100 if I supply the parts, all I need are the bearings (duh), pinioin seal, crush sleeve, and axle seals (just to be safe) right?

Eldoradoman 10-31-2010 12:59 PM

Alright, so we put new bearings in the rear end, pinion bearings were both REALLY bad. Howling/growling noise has gone and the vibration has improved but it's still there a little between 65 and 75mph.

Tires are ok as I swapped them on my 5.9 and they didn't cause any vibrations, so that narrows it down to the rear driveshaft being unbalanced or possibly the rear output bearing on the transfer case?

Candymancan 10-31-2010 02:24 PM

I have the same problem. Once i reach 60mph or higher on my 5.9 the whole vehicle feals like it starting to vibrate a little and i can hear a rumbling sound start. When i look in my rear mirror i can see it shaking a little, vibration imediatly goes away when i go below 60mph and so does the noise, and this to me is really wierd...

I have no idea what it is..

Eldoradoman 10-31-2010 02:37 PM

Quote:

Originally Posted by Candymancan (Post 10372618)
I have the same problem. Once i reach 60mph or higher on my 5.9 the whole vehicle feals like it starting to vibrate a little and i can hear a rumbling sound start. When i look in my rear mirror i can see it shaking a little, vibration imediatly goes away when i go below 60mph and so does the noise, and this to me is really wierd...

I have no idea what it is..

Did you check your transfer case fluid and diff fluid levels? That's where I started, and am down to checking for driveshaft balancing after swapping tires, pulling front driveshaft, changing u-joints....

The new diff bearings made an improvement but the vibe has gone from 'crazy' to 'annoying'.

Candymancan 10-31-2010 02:51 PM

Well the front differential i changed 2 weeks ago with 80w-90 gear oil. The level on that one is fine, the transfercase i changed also. The fluid that was in there was like a dark purple color, and i put in ATF+4 i have the np249 so im pretty sure the level is fine as i filled both till the fill plug was starting to ooz out.

The rear differential i never change, i actually returned the 75-140w Mobile 1 LS bottles, because i heared they are insufficient for alot of Limited slip differentials in trucks (did research) i never got around to getting mopar gear oil and the additive from them as i ran outa money. I also drained my transmission and replaced the filter and gasket

I guss it wont hurt to check the level, i checked it a few days ago cept it was on a litte slanted hill going down and i had to stick my finger down to the 2nd nuckle almost for my finger tip to reach oil.. However this was on the hill so the fluid was probably in the front... I'll drive it up the street and check on a level surface. Btw what color is the differential fluid in yours ? Mine is like a pumpkin orange in the rear, i have the dana 44a Limited slip

Im not going to pull the drive shaft on mine because i still have the 249 TC, i dont want to burn up the VC (even tho its starting to go on me anyway lol)

The noise on mine is not (crazy) but it is anoyying. Its like a rumbling noise that almost seems to change the pressure in the cabin and makes my ear drums wiggle lol.. Sometimes i try to stay around 50-55mph that way it wont happen.. Its wierd how it starts at 60mph for both of us.


EDIT:

I parked the Jeep on a flat surface just now and stuck my fingers down. It does seem a little low, i get fluid right above my first nuckle/below the second on my index finger, another thing i noticed was that the fluid was all foamy and had alot of bubbles in it, and when i messed around with it getting it all over my fingers, the more concentrated it was the darker it looked, it look like motor oil when it turns orangish almost

Eldoradoman 11-17-2010 02:44 PM

K, so putting a gear clamp or two on the driveshaft doesn't do anything, made it worse on two of the four positions.

Would the transfer case output bearing cause this? It's seal is leaking and may indicate a problem....

It's either that or a rear wheel bearing (which I should have changed while doing the diff bearings). There is one u-joint I didn't replace but it appeared to be fine and my mechanic buddy said the same thing when we did the rear diff, it doesn't get hot after driving.

There is a constant squeaking sound at low speed, can only be heard with the window down, could a bearing make that sound? Brakes are all new, the squeak has actually been there since I've owned the jeep so it's not the transfer case (I swapped tc's since).

Thx for any input! I need help on this!


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