6874

I've been chasing a low speed death wobble occurring on a 2007 jku. I have replaced MANY parts in an attempt to calm this down. It only does it going over bumps at speeds between 15 and 30. It has a bit of bumpsteer when going over bumps. Seems to start from the bumpsteer. Once it triggers the wheel will rapidly shake back and forth while tending to pull you left into the oncoming lane until you almost come to a complete stop. I have had tire balance/suspension wear related DW on my TJ back in the day but it only occurred once you were 45 mph and above.

These are the NEW parts that it has... It has the Teraflex Alpine 4" lift with 8 arms and shocks. It has the upgraded Teraflex steering linkage and joints. It has the heavy duty Teraflex front track bar and the Teraflex rear track bar with mount/brace. It has the Teraflex heavy duty ball joints.The hubs are new. The upper control arm bushings on the differential housing have been replaced. It's got new axles and driveshafts. A new Red Head gearbox. It has the Teraflex steering stabalizer. It is running Black Rhino 18" wheels with I think an 18 offset. It also has 1.5" spacers. It has newer Maxxis Razr MT 37" tires.

The bad, it has a truss that was welded on the stock D30 without proper precautions (or it was already bent). The camber on both side is -1.5 degrees. The axles slide in to the carrier without any trouble. The super wide stance of this thing isn't helping I know. She has gone through multiple ball joints and unit bearings. I did try it without the spacers and it reacted the same though. The front diff track bar mount was ripped off and welded back on (it appears to be in the same location as original)

I have the caster set at 5.8 degrees. I have tried as much as 7 degrees caster without change. I have tried as little as 4.5 degrees. I have toe in at .2 degrees. I have tried it a -.2 degrees. I have been through all of the control arm and track bar bolts. Pulling them out and inspecting the holes for elongation and shifting marks. Nothing is evident so I reinstalled the bolts and cranked them down. The tires have been balanced, rotated, etc without effect, but given that it only occurs below 30 and it seems that above 30 centrifugal force keeps it from getting out of hand I don't think that it is balance related. I recommended a beefier front end and ram assist before the 37's and I recommended not so much back spacing on this D30, but it's not my ride so I'm trying to work within her desires.

Moving the steering wheel checking for play the only excess movement I can see is in the rubber bushings used in the teraflex trackbar. I know that there are poly bushings available to replace those stock rubber bushings and that may be my next step. I was also wondering about a frame side trackbar/sector shaft brace. I can see there is movement occurring at the top of the gear box while turning.

Also, I can't help but think that if the bump steer were resolved that it would be better. Looking at the angles It appears that a drop of about an inch on the frame side track bar mount would straighten the lines out parallel. If I had a welder with enough heat I'd do something with that mount even though TF is telling me that the angles shouldn't be a problem.

Got questions? Ask away. Recommendations? Let me know. I'm 47 and I've been working in automotive since I was a teenager, but this has me humbled. I've built four links and radius arm setups and frame work and all kinds of fabrication but I'm ready to burn this one.

6874

My draglink - track bar angles with the proposed drop at the track bar frame side also drawn in

resharp001

It's saturday morning and my brain is bit foggy from working on my engine late last night. It was a very thorough post, but sometimes that is a lot to take in at once so excuse me if I missed this above....and it's a little hard to see from the pic. It looks like maybe you have a flipped DL with that height? based on where the TB looks like it's going on the axle side it's a factory height mount and not a raised mount to match the DL? As far as your question to drop the frame side TB mount.....you should always keep those frame side mounts high and raise the axle side instead. A frame side TB brace is not a bad idea to reinforce the holes in the crappy factory bracket, but a sector shaft brace is just kinda waste of money IMO. If someone feels the need to brace their sector shaft, it's just time to do hydro assist.

Fixing the bumpsteer will likely help as that is what is triggering the wobble, but that does not fix the underlying issue of what is actually causing the wobble. There should be zero wobble at all. I would not put a poly bushing in that TB joint. I would just replace the TB before jacking with that. Metalcloak has a great that doesn't break the bank and their joints are great. It doesn't take much play at all in that TB joint to be the gremlin. IDK if that is your main issue here or not, but TB joints, loose bolts, and bad BJs are the most common wobble culprits. I've had issues with low-speed wobbles that I could trigger in that speed range and at that time it was indeed frame-side TB joint.

I don't like to cover things up at all so if that were my jeep I'd remove the SS for the moment to help torubleshoot and be 100% certain I've got the gremlin worked out and there are no issues once the repair is made. Add it back in the system after that. The jeep should drive perfect without a SS and if it doesn't then there's something to address.

Sixty4x4

Couple of things come to mind here - 1. Have you moved the tires from front to rear vice versa to see if it is actually tire wobble? 2. Those TB/DL angles look pretty steep to me. Lots of diff sideways movement going over bumps which you say start the bump steer. Last thing I recommend is try and get your hands on a borrowed stock wheel set and see if the condition occurs. The mass of 37" tires is way more than stock tires. Remember when they balance there is a safety cover over the wheel so you do not see out of round or wobble as much.