View Full Version : Jeep front end shake/death woble
06-10-2007, 03:57 AM
First let me appologise if this has been discussed. I looked through the 9 pages and didn't see anything with front end shake/death woble in the postings. I have a 96 ZJ 4.0 with a 3.5 RE superflex lift, 31 bfg atko's The lift was done out of both necessity and desire. I was experiencing a front end shake when I hit a sharp bump at certain speeds. Over time it became more frequent and more intense. I have with the lift replaced the lower control arms, track bar coils and shocks. I have also replaced the tie rod with a HD version thanks to a well placed rock. At this point nothing suggested and done has remidied the situation. Reasons I have been given for the "death woble" are alignment, wheel and tire balancing, track bar, lower control arms. All of the above have been either replaced or adjusted and still I have the issue. With the remaining parts that I can replace with heavier duty parts, pieces and supports would be around $700 + my time and labor and maybe a case of beer for the help. As of today it is the worst it has been having happened 5 times since yesterday. I look to you all and your expertise and some guidence. If anyone has experienced this and solved the problem, please let me know what magic you performed. Anyone with any thoughts or insights, they are welcome......selling the Jeep for another vehicle all though a great thought, not a possibility.
Thanks for you time and ideas.
06-10-2007, 05:33 AM
From the experience I have had in this subject....the two main things I would say that would cause death wobble are:
1) Added caster of the front wheels from the lift. This is the angle of the inner knuckle "C" relative to the ground. When you lift your rig, the pinion angle is more than likely rotated upward to account for a little of the added driveshaft angle now that the tcase is higher. This also rotates those inner knuckle C's more toward vertical. This, in conjunction with the toe of the tires being off, will cause death wobble. The toe adjustment now has a multiplied affect due to the caster change.
2) The drag link angle. Not only will having a drag link angle that is too steep cause problems (especially if your still running the stock Y steering linkage), but also if the angle of the track bar does not closely match the angle of the drag link, that could also give bad results if they are too different.
Both of these though are more common with larger lifts. I can't imagine that a 3.5" lift would cause these issues, but you never know....the later model's always seem to have the "lift" issues with even the small lifts.
06-10-2007, 06:11 AM
Caster. I just went through this with a TJ project. Caster fixed the issue.
06-10-2007, 01:54 PM
Thanks for the insight. I was giving thought to replacing the the drag link but the only set up I can seem to find for the ZJ is from Rusty's and I would have to also replace the tie rod with this set up, which I have all ready replaced. Any other maunfactures you have experiance with? Or would you suggest getting rid of the Y config in general? I also was giving thought to a dropped pitman arm to get angles back closer to factory specs. As for the caster, the lower control arm bolts on the Dana 35 I have, have cams on them which when should adjust the caster if I'm understanding your post. I in the many attempts to solve the issue, had the factory bolts reinstalled by a reputable 4wheel parts store and installer and still the problem exists.
Again thanks for the insight.
06-10-2007, 02:20 PM
As it was said above, get a good alignment with correct caster. Make sure all components are bubba-tight and there is no play in the bushings (good alignment place will check for that) Also, shimmy on the front wheel sure does not help.
Additionally make sure your steering damper works well. When I replaced the stock damper on the WJ, it was completely gone, not more than a rod in can. Never really noticed it. Replaced it with an OldManEmu steering damper; it was like day and night.
06-10-2007, 02:23 PM
Cam adjusters may not have enough adjustment. Most cams only adjust about 3/8 of an inch. You may need to swap out the upper or lower control arms with a set of threaded arms. Most of those can adjust up to 3 inches.
You might need to have Adj on both upper and lower and move the axle forward about an inch to improve the drive line angle and Castor angle. It might require lengthening the drive shaft.
The best thing you could do is find a stock ZJ measure the angle through the the knuckles of the axle and try to set yours close to that. More then likely your pinion needs to come down. The problem is you may start having drive line vibrations from too steep of angle on the drive shaft. At that point you might try moving the axle forward.
Some other things to check. The unit bearing wheel bearing. My buddy has to replace his wheel bearings on his XJ about every 10-15k because of wear from the oversized tires and extra stresses from hard off road travel.
Bushings in the track bar. Same buddy can't seem to keep his track bar in good shape. It is a Rusty's. It has broken twice now.
Wore out tie rod ends on the drag link and tie rod.
06-10-2007, 04:08 PM
Thanks for the ideas, keep them coming. Have done the steering dampener, w/ an OME and little difference was noticed. If I didn't mention in the original post this started before the lift was done, I'm sure it has changed all the angles and have taken it in to 2 reputable shops and no one has been able to duplicate the death woble, or provide any insight and until yesterday only one person had been in the car with me when it happened. I appreciate the ideas and as stated above keep em coming! I will keep you posted if anything changes or I have any revelations.
06-10-2007, 04:28 PM
You need a good shake down of the front end with someone there to assisit you. You have had alot of good input already in this thread, and i agree with all of them. In my exp no one single item can be linkled to DW..it can be one or several items. Most times it's brought on by worn components.
You replaced the tierod...new tierod ends as well?
Lay under the front end and have a helper quickly turn the steering wheel back and forth slightly. While looking underneath you want to find anything that moves..tierod ends,trackbar mounts at either end, slop in steering box etc.
Jack a tire unto the air about 6"s, place a pipe or something under the tire and pull up...have someone looking at the upper and lower balljoints attachment to the knuckles. Also check for movement from the front wheel bearing hubs as well.
At 3.5" and 31's i'm betting you have worn component(s) vs castor issues. If all checks out as solid i would take it to a competent alignment shop who has experience with modified suspensions.
Where are you located, we may be able to suggest someplace local.
06-10-2007, 05:31 PM
I am located in Thornton, CO. I have had the ball joints replace once on the passenger side and 3 times now on the driver, the last time I did them. I got tired of forking out $400 bucks and figured I have done everything else why not this. I have a buddy coming out from Alaska and will be here in a few weeks. We have all ready figured on getting under the Jeep and having a look. Again keep the ideas and thoughts coming.
06-10-2007, 11:08 PM
Toyota is runing some pretty good deals on new Tacomas right now. :REOutArchery02:
Good luck pal!
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