Originally Posted by tkagad
I was going over the tracks around 45 mph and the car began violently shaking, along with the steering wheel, until I came to a stop.
I don't have warranty on the Jeep so I'm worried a dealership would be extremely expensive. This mechanic is asking $600 though...
Does alignment alone cause DW?
Ok, your "violently shaking" remark confirms it was true Death Wobble.
First, a new or stronger steering stabilzer (dampener) is NEVER even part of the fix for DW. Calling that part of the cure for DW is like calling a band-aid part of the cure for a skin cancer. The Jeep should be able to operate without a steering stabilizer without it developing DW.
DW can be caused by a multitude of problems or a combination of smaller problems. Most commonly it is triggered first by something... a bump in the road (or railroad tracks) or an out of balance tire. Then once triggered, something has to be loose for the front-end to allow the DW to actually fully develop. Typically that can be a loose passenger-side trackbar mount, bad ball joints, etc.
What I would do is stop going to that mechanic because he doesn't know, really, what he is doing where DW is concerned after reading what you said he told you to do.
Instead, I'd start looking for what is loose... with the wheels on the ground, have a helper start the engine and then start turning the steering wheel repeatedly back & forth while you lay down in front and start closely examining every single part of the front and checking for unwanted side-to-side movement. Especially at where the passenger-side track bar bolts to the axle, ball joints, etc.
Make sure too that you don't have too much toe-in which can encourage DW. I'd also make sure the tires are perfectly (!) balanced since the bigger tires a TJ runs can have a big effect on the front end and even trigger DW when they're not perfectly balanced.