Or wheel hop, or binding.

Not sure what's going on and I am hoping someone here may have delt with the same issues.

I have a 01 Wj with 4.0. 3.5 IRO springs, Core arms... When this problem originally started, there is a section of road I travel that causes the jeep to compress and then fully extend the rear... At 50 mph...

When it started it was like some type of wheel hop... Or oscillating. Slow down to 30 or so and it would go away.

I replaced my shocks and control arms on the rear...

Then it got worse...

So, I decide okay, let's get some new axle shafts and bushings, clean the stuff up. New brake rotors and e brake stuff.

Take it down the road and instead of it only happening at the bump mentioned, it happens as soon as I hit 55. Back to the drawing board.

Alright. Remove wheel spacers, rotate tires.

TC is at 4 and pinion is at 5...

Probably need to drop it a little more.

Has the TC spacer drop...

After rotating the tires and taking the spacers of I managed to get rid of the strange shaking wobbling binding... Thought it was fixed until I hit a bump on the interstate doing 65.

It still shook until I slowed down but it wasn't nearly as noticeable as before.

The differential looked fine, no up and down or in an out play at the pinion ... U joints are all new spicers

Kinda at a loss and not sure what to do now...

If anyone has suggestions or has been through this please post up. There doesn't seem to be many posts anywhere with similar problems.

 

Your notes indicate that you rotated the tires, but did you check balance? What's the condition of the shock absorbers?

 

Shocks I replaced when I went from 2" to 3.5 IRO springs.

They are new. I haven't had the tires rebalanced. But taking the non hub centric spacer off and swapping rears to the front made a huge difference.

I ordered new BFG tires this morning.

When I was cleaning everything up and had the diff open I couldn't see anything wrong, couldn't pry anything into moving... It all seemed fine.

Granted it has 320k on the body it all looked good.

I did run it with the wheels off the ground and axle on jack stands and everything seemed true.

Before all of this I had purchased it with some unknown 2" lift springs... When I noticed one of the front ones were broken I just decided to get new ones...

That's when the problem showed at first...

It kinda feels like some type of binding.... I'm not sure. I would think if it was inside the diff it would do it all the time...

The last time it happened, it wasn't nearly as violent as it was before but it most definitely was there.

Also, I installed a 1" sway bar with new bushings when I did all the other work.

I've had it for going on 13 years... It's always been my daily up until this began... Never had anything similar happen and I can't for the life of me find anything similar discussed

 

I would avoid spacer rings.