Noise, shaking, and mild vibrations at speeds above 40 mph

pixologics

TJ Enthusiast
Joined
Jan 26, 2021
Messages
209
Location
CA
Hi, I recently purchased a Jeep Wrangler TJ 6cyl 1998 with 160k miles on it. Some percentage of miles were from being towed with RV by the previous owner. I'm new to Jeep TJ and while purchasing I did not take it too fast to be able to realize the issues related to noise, shaking and vibrations. It has pretty brand new tires 31" size and have maybe around 3k miles on them.
There is no lift and is stock mostly with hard top. It is making me crazy with the kind of loud noise and shaking that happens at speed above 40mph. Also, at 3rd gear it shakes as if it in wrong gear (which I believe is not). I am not new to stick shifts but am new to SUV stick shifts and that too Jeep. I've tried to match shift gears based on near or close to the gear shift light indicator i.e. to keep it under 2400 rpm mostly.

Questions: Is it normal for a all Jeep TJ to have such symptoms (loud noise kind of unbearable), shaking up (not death wobble) and vibrations that could be felt even under seat? Its pretty much not drive able at high speeds (60mph) without having a head ache. Is it normal?
If not and then what should I get checked for?
Also, are there experts on this forum from Inland Empire, CA area who could see it and suggest?
 
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Check steering linkage. Towing is rough on that. And get the tires balanced. Try and explain how touchy a TJ is for balanced tires to the Tech.
 
Jeep TJ sound issue

TJ sound issue 2

Attaching 2 sample video link above (audio) only. Started jeep from 0mph and accelerated while shifting gears from 1 till 4 gear and max speed was 48mph. Any suggestions on what kind of noise are these? And if it's normal for a Tj to sound this loud at 45mph
 
Some pictures of underbody for troubleshooting.
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you have to grab and move your drive shaft to tell if the u-joint is bad. you cant tell by looking at it. grab the drive shaft and move it up and down, side to side and twist it back and forth. kinda like.... :unsure:never mind . if it clunks around its bad it should be tight with no slop. check both the front and rear drive shafts.
 
you have to grab and move your drive shaft to tell if the u-joint is bad. you cant tell by looking at it. grab the drive shaft and move it up and down, side to side and twist it back and forth. kinda like.... :unsure:never mind . if it clunks around its bad it should be tight with no slop. check both the front and rear drive shafts.
Thanks Just saw couple of videos to further understand it, will be going to inspect it soon and get back to you.
 
Update I looked into u-joint and don't find any loose ends.
I further tried to drive it on Freeway and city as well on speed above 45mph and tried two approach:
1. Pressed the clutch and the sound was significantly less.
2. Put the transmission in Neutral on high speed and I hear not much noise.

Can anyone suggest where to look up further?
 
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You didnt leave it in 4w drive did you? My son has a YJ and he had put it in low trying to get out oof ditch. then the vibrations started. Turns out the transfer case was shot. 500$ later back to normal..We had to change the front U joints at one time that cause a vibration..JEEP.. Just Empty..Every ..Pocket.. yj
 
You didnt leave it in 4w drive did you? My son has a YJ and he had put it in low trying to get out oof ditch. then the vibrations started. Turns out the transfer case was shot. 500$ later back to normal..We had to change the front U joints at one time that cause a vibration..JEEP.. Just Empty..Every ..Pocket.. yj
Thanks for sharing. I have no idea if it was driven in 4H for too long or what. I did try to drive in 4H and it is rather less noise than 2H.
I am new owner so can't say much about how it was driven by past owners.
 
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Update- Solved the issue. The problem was with the u-joints in the rear. Got them replaced and no more weird noise or vibration.
Still some minor shudder if I overload engine. A friend said engine mounts could be replaced as well. Need to see if it's easy to replace engine mounts as DIY.
 
Trying revving the engine out a little further between shift. I shift gears at about 3k-3200 rpm normal driving. More if I need to accelerate to match traffic.

Engine mounts are not too hard, but might seem a challenge for someone not mechanically inclined. Assume you have some tools? There are a lot of great YouTube videos that should give you some context on how hard certain repairs are.
 
Ignore those EPA shift lights...

Engine mounts is a good thing to check. Rev the engine while looking at them and see if you can see/hear anything out of place from them. Another possibility is the transmission mount, which is relatievely cheap and easy to replace (in my opinion). If the shudder happens iwhen you rev n neutral then I believe you can rule out the transmission mount.