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Unread 07-02-2007, 11:01 AM   #1
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Join Date: Apr 2007
Location: Huntsville, AL
Posts: 20
Unknown knocking/vibration

Howdy folks. I have a 97, 4.0, 5 Speed, for those that may be able to assist. I've had this TJ for a few months now, and have used the 4WD on several occasions, two of which I've experienced the symptoms below.

The knocking/vibration occurs whenever I have 4H engaged, have little to no traction (eg. mud/snow), and the RPMs are above ~2500. Once I reach higher RPMs it feels as if the transfer case starts shifting from side to side (although I have not been under the jeep while testing this to see what is actually occuring). If I let off of the gas or shift into the next gear the knocking subsides. So far I've only gotten the knocking while in 1st gear.

I've never felt anything like this before, in any vehicle while in 4WD, and am curious if this is something I need to be concerned with, or if this is common in a low traction, high RPM situation.

Any help is appreciated, and I'll be glad to answer any questions I can.

rwjeep is offline   Reply With Quote Quick reply to this message
Unread 07-02-2007, 12:24 PM   #2
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Join Date: Oct 2006
Location: Kalifornia
Posts: 836
Sounds like two different issues as far as no traction then knocking with the T/C moving about. Id check the rear trans mount, the one on the skid plate. Might be broken even though theres a retainer rod of sorts it still can get squirrly and make noise, there may even be a rock jambed between the two like I had once. Sure made for some weird noises.
Regarding the loss of traction?? got me other than the 4wd not engaging at all, cant see what RPM would have to do with it.
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Unread 07-02-2007, 01:09 PM   #3
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Join Date: Apr 2007
Location: Huntsville, AL
Posts: 20
I'll have to take a look this evening.

What I meant by lack of traction, isn't a loss really, it's just that I only have noticed the knocking when I have little to no traction. Meaning 4wd is engaged, and the wheels are spinning, but cannot grab. Like in sloppy mud or snow/ice.

The higher the RPM's, the faster the wheels spin, since they aren't grabbing anything. I suppose I would get the same knocking if I were to engage 4WD, and drive down a dirt road with higher RPM's.
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