96’ LC is shuddering to the point of not driving it. It is worse under load and the one place you don’t feel it is in the steering wheel. I have more or less narrowed it down to the differential dynamic dampener (or fill in what you call it). I read that some people simply remove it?? Why would that stop the vibration? If it does why is it there to start with and if it is removed are there potential long term problems that may arise? Sorry for the compound question but this thing is driving me crazy and not driving me anywhere else.
Bad vibrations
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Solution
MissahPapaJ
Snack Lah Bler!!!!
First things first buckaroo, have you checked U-joints? But I believe you’re referring to the viscus coupler in the T-case. Lots of things can cause vibrations try to be more concise. I’d maybe give a symptoms search for 80 series viscus coupler issue and see if something pops up.
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- #4
Head gasket? Motor mounts look fine. The transmission mounts look fine. It passed the test I found for a viscous coupler although shuddering or serious vibration was not listed as a symptom and it does not have the tightness when that goes bad but why not check. So I did. U joints were the first thing I suspected when this vibration started. Checked those too. I had a friend drive it thinking I was missing something simple. After saying “That’s weird” spent an afternoon picking around checking and re-checking. He is the one who noticed thing bolted to the transfer case and it took us a while to ID it as this dampener. I am curious what the things you mentioned could cause the vibration. It is not in the steering and it does not feel like it is in the wheels or suspension. Again it is most significant under load like going up steep incline.
I'm going to assume you haven't removed the driveshafts since you never mentioned it. Pull 1 driveshaft, lock the center diff and go for a test drive. You can also properly check the UJ's with the DS removed. If the vibration remains, reinstall the D/S and remove the other D/S and repeat. This will help narrow things down. I very much doubt the vibration damper on the transfer cas has any influence on your problem.
MissahPapaJ
Snack Lah Bler!!!!
Have you removed the drive shafts and checked if the u-joints move freely? No binding also if doing this check front and rear pinions for bearing play and check flanges on T-case for play. I had a k1500 come through my shop not too long ago and the u-joints were not sloppy but it had a vibration I removed the drive shaft and the forward u-joint was binding real bad I replaced the joints and the vibration went away.
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- #7
I did check the u-joints for play but not for binding. It seems worth a shot. Sounds like next weekend is going to be under rather than in Elwood. My wife named it and it is better than what I have called it lately. By the way this problem did not suddenly appear. There was probably a month when other people were telling me it was all in my head but that is not where I felt it.
Is there a lift installed? Does the vibration increase with speed? If there is a lift installed, if the pinion angle and transfer case output shaft are not parallel, can cause vibrations. The driveshaft removal method, already suggested, is a good troubleshooting procedure to find this out.
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- #9
No lift. The vibration does seem to increase some speed however I’ve not taken it over 40 due to the vibration. If I am driving slowly up a steep incline the vibration is pretty bad so in that sense it doesn’t necessarily increase with speed it increases with torque or load. I agree about removing the driveshafts. That is my next step.
unbolt each end of the driveshafts one by one and feel by hand the movement of them, when bolted in place you cant feel a bad UJoint as much
start with the rear and work your way forward
also, a binding slipyoke can cause really bad vibes, almost like driving over speed bumps endlessly when under load
I had a similar thing years ago and it was old hardened grease in the rear driveshaft slipyoke. i marked its orientation and took it apart, cleaned out the old grease and regreased with MolyGrease - been fine ever since
start with the rear and work your way forward
also, a binding slipyoke can cause really bad vibes, almost like driving over speed bumps endlessly when under load
I had a similar thing years ago and it was old hardened grease in the rear driveshaft slipyoke. i marked its orientation and took it apart, cleaned out the old grease and regreased with MolyGrease - been fine ever since
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MissahPapaJ
Snack Lah Bler!!!!
How are your rear arms and pan hard bar? If those are fudged all off you could be experiencing the rear end wagging which will send all input to the T-case… Nissan pathfinders used to get real western when these parts were sloppy.
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- #13
Sorry it has been a while. I took off the front drive shaft and looked like it was a bad u joint that had bound up so it felt tight until it was off. It sat for week or so then I cleaned it up and really looked at it. Turns out it doesn’t matter what shape the inside is in when it is being held by a broken shaft. See picture I hope. A new shaft is on its way.
MissahPapaJ
Snack Lah Bler!!!!
Ya buddy! that’ll do it glad you finally found the culprit, some times it pays to spend the extra time and pull parts for inspection.
Chasing my drive shaft vibes too... Turns out we are twins!
Front drive shaft vibes were hidden by 2 things, my old mickey 35" MTs (new AT3s are much smoother) then finally added Slee Caster plates, which exasurbated the vibrations, which lead me to a Double Cardan requirement (still might be the case) but 75% of a functional U-Joint is most likely the main culprit.
Greased mine about a year back, maybe 1500 miles and it's now dry (lots of puddles and dirt), must have been on the opposite side for me to miss the giant missing cup section.
Great post, hopefully more find this and try a $75 u-joint before going down a rabbit hole like I was about to.