Here's the deal. I've got an 89 YJ that has what is commonly described in the Jeep community as a "Death Wobble". Here's what happens:
At speeds over 55-60mph, *sometimes* (it's not often) the Jeep begins to VIOLENTLY shake. It doesn't happen all the time, and I can't make it happen on purpose. And when I say violently shake, I mean it. I lose control of the Jeep. If I slow down to about 45 it goes away. I can then resume my 60mph cruising speed and everything is fine - but it "feels" like it wants to happen again.
It's scary as hell when it happens, and if it does it to me this winter, it's going to mean an accident.
Observations and notes:
1. The suspension is bone stock. No lift.
2. The stabilizer link bushings have been replaced (suggestion from another guy), and they were obviously shot to hell anyway. Problem still exists.
3. The alignment has not been checked, but it tracks perfectly straight if I let go of the steering wheel. It doesn't pull to either side.
4. You can "feel" it beginning to happen. It occurs mostly at speeds above 55, and on roads that aren't glass smooth. When you hit a bump, you can feel the oscillations beginning (it's particularly noticeable in the steering wheel). If you accelerate during this "pre-death wobble" period, it will surely set the process in motion and the Jeep will begin to shake violently (it's so bad, you can't even see out the window).
5. If you feel it coming on and decelerate, it goes away. You may then resume the speed you were just at and it'll be fine. For a while.
6. It seems more likely to occur if you hit a quick succession of small bumps or imperfections in the road. Interestingly, flying over railroad tracks (a REALLY good bump) won't do it. I've tried - over and over.
7. My dad has seen a Jeep do this while driving down the Ohio Turnpike (I-80). The front tires were jumping up and down, and the driver had a difficult time keeping the vehicle on the road until he slowed down. Just like me, he resumed his speed (passed my dad) and all was fine.
8. The steering wheel doesn't move back and forth. It's just easy to feel the oscillations beginning through it. The shaking is a violent up/down motion.
Listen, I need to get this fixed or I can't drive it in the winter. It's one thing for this to occur on dry pavement. It's quite another for it to happen in the snow. If this happens in the snow and ice, I will probably roll the Jeep or crash it into something at the very least. It's unsafe, and that's an understatement.
I've asked this on Jeep boards before, and I can't get any definitive answers. Everybody that replies says "I had this happen to me" or "My friend's Jeep did this and here's what I did...". That's all well and good, but when I add all the suggestions up, I also end up with a brand new suspension by default. I can't afford to chase it down that way. I need REASONED answerers, and I need them from people who understand suspension geometry. I turn to arfcom, because we really do have some exceptionally bright and talented people here.
If you tell me "maybe it's the ball joints", I need to know how to verify this DEFINITIVELY without putting new ones in first. If you tell me "check the tie rod ends", I need to know how to do this DEFINITIVELY without purchasing new ones (and having the vehicle realigned again). Basically, I can't afford to just start swapping parts until the problem goes away. I know that will work, but I don't have the money or the time to approach it this way. I don't have a garage or even a paved driveway to work on this thing, so doing suspension work is VERY troublesome and difficult.
I need this pinned down, and I need it backed up with rational thought. I can't be outside in the cold lying on a dirt driveway for a month chasing dead ends.