Over the past 2 weeks I had noticed a clunk when i started off in 1st. After getting a friend to watch uder the JK while starting off and it appears I am getting severe axle wrap. It is rotating far enough where the bump stop blocks hit the rear sway bar links causing the clunk. I would say the joint at the axle is moving a good 4 to 6 inches up as I start off. If i take it very easy it will not occur... but normal driving cause the rotation. Has anyone else had this issue with a Full Traction 3" Ultimate? None of the brackets look broke... or the controls either... any ideas?

 

the axle should not be able to twist like that unless one of the control arms is not doing its job. You are saying that the axle rotates the pinion yoke up and down when you take off? First thing I would check would be upper control arms. But I don't know, as I have never seen that on any of my coil sprung vehicles.

 

Ummm, axle wrap is very common on leaf sprung vehicles, especially spring over axle configurations. This happens when the leafs are torqued and they take on more of an "s" shape as opposed to a smiley face shape.

I've never seen or heard of axle wrap on a 4 link coil set up unless something is broken. I don't see how it could even happen. I'm thinking you've got a control issue. Sorry, make that a control arm issue.

 

Yeah, I'd check all of your control arms and make sure the jam nuts are tight.

 

you have a blown out rear lower control arm bushing(s). if you got your kit about last year summer, FT had a bad batch of bushing (as well as procomp and a host of other companies that use energy suspension as their supplier) and they prone to go bad very quickly. they have since fixed this problem and you should contact them about it. i know they had been sending out replacements free of charge.

 

the human jeep encyclopedia has spoken.

 

As long as all the mounts where the control arms mount to the frame and axle are intact, with good welds and no cracking, I'd pull all the bolts out. You may find egg-shaped holes or worn bolts. It could also be worn out bushings, flex joints or heim joints (I don't know which your FT arms have). Something is giving you fore and aft movement where you should only have rotational movement. One of the reasons I didn't go with FT is that I heard that they had problems with their bushings or heims.

Before pulling the bolts out, if you have access to a 24" or 36" pipe wrench, I'd size it to the axle and come in from the rear and try to go down with the wrench like you're trying to rotate the pinion up. You should see some for and aft movement that shouldn't be there at one or more of the control arm pivots. My guess would be that it would be the uppers.

 

the FT arms used poly bushings with a crush sleeve and the bad bushings simply crumble. however, the arms are threaded and if you ask, you can get a spherical kit to replace the poly setup.

the heims are fine. i have been using them on my TJ for years and without any problems. the problem is with the batch of poly bushings they shipped out with their kits last year.

 

Wow - I think you nailed it on the head. It must be bad bushings... i noticed alot of grease seepage from the upper mounts... blown! Thanks for the input Wayoflife! I'll cal FT tomorrow!

 

Just removed the lower control arms at the frame mount - bushing blown! Both sides! Simple fix - i like that!