New Vibration

ItchyDong

Easily Offended
Supporting Member
Joined
May 20, 2020
Messages
622
Location
Dothan, Alabama
So I installed a lift (DPG super ultimate), mml, new tires and wheels on the LJ about 15k ago. All of the sudden I’ve got vibes lightly beginning at about 30 mph and gets worse with speed up to 70. I had the tires rotated and balanced and no change. Is it possible that my pinion angle is the culprit after 15,000 miles of vibe free driving, or am I barking up the wrong tree. I’m going to start investigating tomorrow. Any words of wisdom?
 
Last edited:
I once put on fresh rear coils- had an awful vibe with only 1/4” of change.
 
  • Like
Reactions: ItchyDong
Make a list of common possibilities and start investigating. Chasing vibes can lead to a need of sanity check, and when you get to that point, come back and we will do our best to square you away.

At this point you are doing whole lot of barking at something, and we are just as clueless as to what you are barking at.

Once you run out of ideas, check your rotors. Take a wild guess how much hair I lost by the time I figured that out.
 
  • Like
Reactions: ItchyDong and AndyG
I’m going to start investigating tomorrow. Any words of wisdom?
:unsure:


wisdom (2).jpg
 
  • Haha
Reactions: ItchyDong
So I installed a lift (DPG super ultimate), mml, new tires and wheels on the LJ about 15k ago. All of the sudden I’ve got vibes lightly beginning at about 30 mph and gets worse with speed up to 70. I had the tires rotated and balanced and no change. Is it possible that my pinion angle is the culprit after 15,000 miles of vibe free driving, or am I barking up the wrong tree. I’m going to start investigating tomorrow. Any words of wisdom?
The vibes are definitely driveline related because they increase with speed.

Remove front shaft (tie off at the frame) and see if they go away. If they don’t you probably have a bad ujoint or centering ball in the rear driveshaft. If no vibes, reinstall front shaft and remove rear driveshaft. If vibes don’t go away you have a bad ujoint or centering ball in the front driveshaft.
 
The vibes are definitely driveline related because they increase with speed.

Remove front shaft (tie off at the frame) and see if they go away. If they don’t you probably have a bad ujoint or centering ball in the rear driveshaft. If no vibes, reinstall front shaft and remove rear driveshaft. If vibes don’t go away you have a bad ujoint or centering ball in the front driveshaft.
I can’t remember where we are all on this but pulling the front driveshaft is your go to first move on suspected driveline vibes by many shops
 
  • Like
Reactions: ItchyDong
So I just finished test driving it with both driveshafts out one at a time. The vibe is still there and really noticeable at about 60-65 and especially when letting off the gas at about 65 in gear and letting it decel. It did seem a little better with the front driveshaft out vs. with the rear out. If I’m not mistaken, doesn’t this rule out rear pinion angle? I’m going to replace the u joints anyways because the rear driveshaft is loosey goosey.

I’ve never replaced u joints with that cardigan joint that’s on the front shaft near the t-case. Just a standard ball joint c-clamp set up will work for that?
 
So I just finished test driving it with both driveshafts out one at a time. The vibe is still there and really noticeable at about 60-65 and especially when letting off the gas at about 65 in gear and letting it decel. It did seem a little better with the front driveshaft out vs. with the rear out. If I’m not mistaken, doesn’t this rule out rear pinion angle? I’m going to replace the u joints anyways because the rear driveshaft is loosey goosey.

I’ve never replaced u joints with that cardigan joint that’s on the front shaft near the t-case. Just a standard ball joint c-clamp set up will work for that?
I remove the shaft, use a socket on one side of the ujoint and two 4x4’s on the other side with a gap in between so I can use a hammer on the socket to drive the u joint out one side, being careful not to hit the ears, remove the cap and take out the ujoint, then keep going. It will make sense as you get to the next one. There are videos of this method. If you have to do the centering ball there are ways to do that too with basic tools.

I put new ones in using the socket and hammer method too. One at a time. Start with the easiest one, the one on the non-DC end so you get used to it. Don’t lose any needles. Be careful pulling the caps. Takes 30-45 min to rebuild the whole shaft. Occasionally I have to shave a bit off the snap rings with a flap disk to get everything seated.
 
Last edited:
So I just finished test driving it with both driveshafts out one at a time. The vibe is still there and really noticeable at about 60-65 and especially when letting off the gas at about 65 in gear and letting it decel. It did seem a little better with the front driveshaft out vs. with the rear out. If I’m not mistaken, doesn’t this rule out rear pinion angle? I’m going to replace the u joints anyways because the rear driveshaft is loosey goosey.

I’ve never replaced u joints with that cardigan joint that’s on the front shaft near the t-case. Just a standard ball joint c-clamp set up will work for that?


1649960439499.png


don't use a ball joint press or c clamp. Get a socket that's just smaller than the u-joint cap, another one that's big enough for the cap to fit into (or some blocks of wood like @JMT describes above), and pound away.