Drivetrain noise - can't quite put my finger on it.

[Geonovast]

Something's going in the drivetrain on the 99 XJ. Shortly after I bought it, I was getting a shaking when I would use the brakes. Checked the rotors, sure enough, they were warped. Replaced them.

 

The ride's still not quite right. At 50+, I have a barely noticeable shake, but it's definitely there. There's still a very slight shake when I press on the brakes more than 1/4 of the way down. This shake feels like it's coming from the back. The front pads were brand new, and the rears look to be about 90%.

 

I'm also getting a whining noise from the front. I tried opening the window, but wind noise just drowns it out. The volume and pitch of the whine is preportionate to speed, not RPM. On top of that, every once in awhile when starting out, I can hear a quiet clunk, and the truck jerks forward a bit. When stopping, it seems to happen every turn of the wheels. It doesn't do it when it shifts.

 

I've checked for slop in the wheel U-joints, and both driveshafts... as well as the balljoints, wheel bearings, and pinion bearings. I'm at a loss as to where to go next.

 

99 XJ - Auto - 231 - HP D30, 29 spline 8.25.

 

I can take it to a parking lot, and try running around with each driveshaft removed if you think that'll help. (Gotta love sealed output 231s)

[beaterjeep]

Did you check the tracbar in front and swaybar in back? Also, what kind of whining are you getting? Low pitch, high pitch, constant, intermittent, etc.?

[Geonovast]

It's a constant whining, usually shows up once I get above 20 mph. The faster I go, the higher pitched it gets, and the louder it gets.

 

When I checked the trackbar for slop(before I bought it), it was perfectly fine. I had Jo sit in it while running, I got under and had her move the wheels lock to lock several times, and there was no slop anywhere.

 

I haven't directly checked the rear swaybar, but when I had the back tires off to check the brakes, nothing looked out of the ordinary. Tomorrow I might dissemble the rear brakes and put them back together... maybe that'll tell me what's going on. Might even go far enough to pull the unit bearings off the front. I'd rather not pull the diff covers, but I think I might have to.

[Akula69]

Could the clunk (and the slight forward movement) be the positraction rear end? (Only if you have the dana 35 I believe).

 

Ralph makes that noise when we turn corners...I put an additive in the diff and it went away for awhile.

[sinkrun]

This is crazy except for the clunk you just described the same noise in my 99xj that were headed out to check for inspection today I had high hopes it would be something obvious.

[ajpolitz]

99XJ has something to do with the Drive shaft.

My 99XJ whined like a b****h. XJ and WJ for 1999 all had the same issue.

 

Anthony

[Geonovast]

99XJ has something to do with the Drive shaft.

My 99XJ whined like a b****h. XJ and WJ for 1999 all had the same issue.

 

Anthony

 

Which shaft? I think I'm going to remove the front shaft tomorrow to see if there's any difference.

 

Still doesn't explain the clunk though. :hmm: The AC compressor whines too, so that's making it even harder to track down.

[ajpolitz]

Mine was rear, Jeep actually had a fix to install a shorter drive shaft but it did not fix the problem.

It sounded like the pinion gear in the rear to me but Jeep claimed different.

Never got rid of the whine until I sold it. ( Had to buy a bigger truck, second child was on the way )

 

My 2008 FJ had BUMP STOP! - Traded that b****h in after a year of owning it. ( Costly mistake )

 

A-

[streetjeep2.5]

Back in the days I worked at a Ford dealership, the 4x4's would get a clunk in the front with the wheels turned. Was one of the ujoints on the front axle. Not having a 4x4 mancie, I "assume" there is a ujoint or something similar on the front axles. Could be the front clunk, and if worn, would think it would let there be some shaking when braking. Hey! I'm a poet and didn't know it! ;)