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Rear "shudder" upon turning after long, 45mph+ straight run.

TacticalFats

NAXJA Forum User
Location
New Joisey
97 xj, 4.0, auto, D35 limited slip, 242 (police package), ~49k miles (yes, that's it).

What has been happening: After driving in a straight line for more than a few minutes at speeds over 45-50 mph, I come to a stop (either at the top of an off-ramp or at a light/stop sign), then turn left (haven't noticed if it does it turning right, too), the rear "shudders". Only seems to does it after a protracted, medium to high speed run. Almost like a back tire is flat. Definitely coming from the rear...

Running heavier weight synthetic with modifier in the rear, changed in the spring.

Any thoughts?
 
A month later, and I got around to greasing the slip yoke. It didn't help.

When starting off and turning even a little, it seems as if the rear is slipping and "catching up"....very hard to describe.

A past TJ (2000) I had, with a D35 also (but w/o limited slip) also did it, only more pronounced. That also had ~40-50k on it, 3 spd auto. I traded that before I ever resilved it.

U joints seem tight; there's no pronounced "clunking" going on at all.
Thoughts?
 
You say you are running a "heavier weight synthetic". Does the problem occur when running the specified weight w/modifier?
 
I had a similar situation in my FS Bronco when I had Ford dealer service the diffs and they said they used the modifier, but the problem went away when I changed the fluid and used the modifier.

Are both the rear tires very close in diameter? A difference can cause problems. Even though tires are marked the same size they can differ between brand/manufacturers by substantial amounts.
 
Head to your nearest Ford dealer. Pick up a bottle or two of XL-3 friction modifier, they're small. Add one to the fluid, drive long enough to warm it up then do some figure-8's in a parking lot for a minute or two. That should take care of it, if not add the other bottle and repeat.
 
Sorry, just saw this. This only happens after running for awhile. Especially noticable after a highway run.

Same EXACT issue I had on my tj, which didn't have the clutches. I'm stumped...which isn't saying much since I don't know much about rears.



did fine in the summer and only started doing this after gettin cool. sounds to me the lube is to thick for the cooler weather with the lsd and it is causein a prob. try goin back to thinner lube with additive and see it that helps.
 
I'm going to check it tonite (pull the plug). I might add a second bottle of modifier.

I found some threads on some other forums (not jeep-specific) that mention that LSD's don't like Mobil1, which is in there....heavier-weight, no less.

I'll add another bottle of modifier after I check the fluid (after I drain it to the appropriate level).

I'm even wondering if the greasemonkey who "did" it for me actually did anything at all.
 
Bump.

I haven't put many miles on this thing (it's at 57k now), and it still does it, even on short trips. Like the rear slips slightly, with a rumble.

Thoughts?

Sent using the Tapatalk app on my Droid X...
 
Assuming it is indeed the rear diff making the noise- any chance it's in the tcase? Usual check for noisy diff clutches is come to a stop with the steering to full lock. Brake torque a little and roll forward slowly. That's when clutches are loudest.

Have you done a good once-over of the whole undercarriage? Seals, bearings, anything out of whack. Reason I ask is you mentioned an open-diff TJ doing the same thing, yet there's no way an open diff can really have an issue that acts like clutches. The internet is a poor substitute for a test drive.
 
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After a long, straight run is when it does it. Loading the rear as you described won't duplicate the issue.
I drove ~20 miles on a fairly straight road at about 50mph which ended at a t intersection. I stopped and made a right turn. Upon starting, it sounded like the rear diff was "breaking loose" as I turned, which leads me to suspect that the clutches are sticking.

I rarely drive this thing in the summer (I have a company car and a yj) so when the heat breaks, I'm going to crack open the rear different and do a proper fluid change.

Sent using the Tapatalk app on my Droid X...
 
Did a fluid change. From the looks of it, the turd that said he did the change for me back in late 08/early 09, didn't.

I put in the standard weight (not the heavier weight that's specified for towing) and friction modifier. Seems a bit quieter; I'll know after the next trip down to my trailer at the shore.

Also, upon checking further, it appears that my 2000 TJ (which I owned from 2003-2005) very well may have had a limited slip, as well. I was unaware that TJ's ever came with them, so this makes sense....

Hopefully, this resolves my problem.
 
Necro bump. I was searching for another issue I'm having and was annoyed that people rarely post what fixed their problem.

I added a second bottle of modifier to the rear and it resolved the issue. I just put this back on the road after sitting in my garage all summer and I noticed it's doing this again, although only slightly and only after the specific conditions are met (long, straight drive, stop, then a 90* or sharper turn).

Hopes this helps someone...
 
I had this issue. Started after the diff fluid was changed at noe of those EZ-lube places (was feeling lazy that day...). It was the clutches in the factory trac-loc limited slip. Drain the diff, replace the oil, make sure you add the friction modifier.
 
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