After much research here and on other forums my deathwobble is now resolved. This will be a rather long post as I want to be as detailed as possible. My DW was caused by a couple of problems that I have seen documented here before and one that I have not seen. Before I installed the lift below I had minimal front end vibration that I attributed to out of balance tires.
Many thanks to the following threads and contributors:
The End-all, Be-all TJ Alignment thread"
Severe death wobble on new lift
ps. This fixed MY issues, but I am in no way saying this will fix YOUR issues
Scroll to the bottom for Cliff's Notes if you don't want to read everything.
2006 TJ Rubicon - 100k miles ( I purchased 05/11 with 90k)
Factory Moab wheels
245/75/16 Dunlop A/T tires with good tread.
Broken factory swaybar link
I installed a lift with the combo of parts below:
- 3.5" BDS Springs
- Bilstein 5100 shocks
- BDS rear swaybar links
- BDS rear trackbar relocation bracket
- BDS xfer case drop
- No front swaybar links - bad threads on one of the axle end ball joint studs
- RC adjustable front LCAs
with flex joints on the frame ends
- RC adjustable trackba
r - the one with the TRE on the frame side and clevite bearing on the axle side.
I installed the lift in my garage by myself. This was the first lift I've done on a TJ but I have done leaf sprung vehicles before. I consider myself a competent amateur mechanic who has a good understanding of how the TJ suspension works. I did use a torque wrench to get everything back to factory or RC specs. While torquing the front trackbar I broke the axle side bolt. I went to my local auto parts store and bought a 3/8 Grade 8 bolt/nut/washers that had the proper length shank torqued it to 60 ft-lbs.
After the install I drove two miles and experienced the dreaded DW at ~45mph. I seriously thought the front axle was about to come out from under the front end. I got home and pulled back into my garage to do an inspection of the front end. I rechecked torque and everything looked fine so I decided a trip to the alignment shop was in order.
The alignment shop found that my toe was off (I don't remember the numbers but I think I was around .7*). They also reported that the camber on my drivers side was over a degree and that my caster was 8 degrees (on the edge of acceptable factory spec) but resulted in poor pinion angle. They thought that either my axle or the C was bent. They adjusted the toe verified that I had correctly centered the front axle. They also checked for tightness of all bearings, bushings and links. After leaving the shop I drove around for a bit and did not experience DW. I intentionally hit some potholes and noticed the shimmy start, then work itself out.
I had a 350 mile trip to make the next day (I know, don't do a project like this before you have to make a trip so no lecture needed
) I had no issues for the first part of my drive (two lane roads for several miles, then I75 out of Atlanta). Those of you in the area know how awesome the construction is in that area but I still didn't have any DW. I would get a minor shimmy that felt like DW was about to start but would quickly dissipate. After stopping for lunch I got back out on the highway and had DW which forced me off on to the shoulder until I got down to 10MPH. I regained speed gently and had one more incident. After that I determined I could go 64mph exactly and not experience any issues.
I stopped for gas and rechecked tightness of the trackbar bolt. My torque wrench clicked at 60 ft lbs again so I thought I was OK. I left the truck stop and headed back to the highway. As soon as I got up to 50MPH on the on-ramp DW hit without warning so off to the shoulder I went. After a second bout of DW it leveled back out and I had no more issues (other than overly clenched but cheeks for the rest of the ride
The next morning I stopped by a tire/repair/body shop that I know does quality work. I knew I needed (OK, wanted) new tires so I placed an order for a set of 285/75/16 Cooper STTs and talked to Clint, their front end guy. He was familiar with DW and has over 20 years of experience working on 4x4s so I felt confident he could resolve my issues.
Two days later I came back and their mechanic pulled me onto the alignment rack. I knew we needed to adjust the LCAs to dial in less caster but wanted to get it setup on the alignment machine so we knew exactly where we started and ended. While setting it up he determined that my drivers side front wheel was bent so he swapped that from the front to rear. Once this was done he could get accurate readings. The toe was off again (.8*) but the camber was now showing to be correct. The first shop I went to did not diagnose the bad wheel so they thought the camber was off, then set the toe incorrectly. Granted, my driving with DW could have knocked the toe out of spec so I won't fully blame them for doing this wrong. Clint also found that the trackbar had too much play at the axle side. He installed a 10mm bolt which made for less play. The bolt holes were still round so there was no need for repair there. He reset the toe and adjusted the LCAs to give just under 6* of caster so that the pinion pointed straight toward the front of the transfer case output.
We took it for a ride and had NO DW!!!! I could feel some vibration but it had no hint of the escalating shake that I had come to fear.
We came back and installed the new tires and off I went with a newly safe jeep. I've driven several miles since and haven't had any more issues. If anyone in the Bowling Green KY area needs a recommendation for a shop with someone who knows a lot about our front ends send me a PM and I'll send you the info (and no, I am in no way affiliated with the shop).
: Cliff's Notes
- Bent wheel on front end
- Caster too far positive and bad pinion angle (RC x-flex LCAs take 2 turns per degree of adjustment
- Too much toe in
- Trackbar bolt too small