Wow, that's horrible!! I did a cursory look in these locations for cracks but the frame paint makes it hard to tell if there's a minor crack or not. In my photos above I couldn't see that crack on the opposite frame rail very well at all, it looked just like a crack in the paint. It wasn't until I ground it down that it was really obvious.
So what I ended up doing is what everyone doesn't recommend which is throw money at the death wobble problem: New Delta arms & panhard bracket, new MAF steering upgrade kit with new TREs, new bushings in panhards, new adjustable LCA's because my old ones were bent making my thrust angle slightly off (.25 deg), full front axle rebuild including new spindles/bearings with (IIRC) 35 ft-lbs on the bearings and preload on the trunions at the higher end of the spec. In addition to this, I did the additional welding on the side opposite the steering attachment as shown above.
Result:
Towed my ~3500lb M101A trailer setup down to AZ like a breeze. Drove better than it ever has, by far. Amazing difference, I think largely due to the Delta panhard bracket--that thing is truly an amazing bang for the buck! I was so stoked all that work and money made such a H-U-G-E difference! At the end of a 10-hour drive I was fully relaxed like I drove my Subaru down...usually I'm totally exhausted.
Then I drove the hell out of it offroad down in AZ for a week. I ran into town one day with three little kids and
death wobble randomly hit again at 65MPH in a very terrifying way. This truck has
never, ever done anything like that before especially without warning and at such a high speed. I made it back onto dirt OK, drove it around offroad for many more hours at high speed with no problems. At last had to drive 1.5h drive on gnarly washboards to get to pavement to head home, death wobble again happened when I hit pavement only much more predictably--anything over 50MPH and it would 100% happen. I could feel it very obviously in the wheel building up. I had to air down and limp at 48MPH for 3 hours to Vegas where fortunately I had previously made an appointment to get Nitto's put on. What's interesting is that a few hours into this drive I could tell that whatever was causing the wobble had settled down because it was no longer borderline (at 48MPH it was very obvious I was on the limit of DW and had to slow down for all major bumps)--I think something settled down in my crappy shot tire?!? Did my OME stabilizer fade on my gnarly high speed washboard drive and it took an hour or two for it to start working again? I'm not sure.
So anyway I got to the shop and got the new tires installed and everything was instantly perfect. The Nitto's have eliminated all wobble, entirely. I previously had Cooper AT3 XLTs and I think they have been garbage since Day 1. Even with the recent overhaul I could still feel a very distinct minor wobble in the wheel when hitting a certain kind of bump, and that has always been present with these tires regardless of rotation, newly balanced, etc. But with the Nittos that distinct wobble is
entirely gone.
However, I'm not convinced this problem is solved just with the new tires. I have a post in this very thread from 2018 where road force balancing eliminated my wobbles and I thought I was good to go. That was true until I went to rotate/balance my tires last spring which randomly caused death wobble to return. I spent all day limping between tire shops until someone could get the stupid Cooper AT3 XLT tires balanced properly even on Road Force machines. Some shops were saying I had bent rims, some said they were fine.....uh, what?!? On my latest tire change they said my rims were totally perfect! I think they were covering up shot tires.
I started looking into this more, beyond Land Cruisers, and came across this great article by Thuren Suspension which is specific to Dodge Ram's but it's an interesting read if you have death wobble and this mimics my experience entirely:
www.thurenfabrication.com
Basically, their conclusion is that more caster can make DW worse, minor loose components are not a major contributor to recurring DW and that certain tire types and steering stabilizers, especially stabilizer location, are primary players. I found this article by looking into the steering stabilizer as a culprit only because it's literally the only thing I haven't replaced in the DW system and my little engineer mind can't wrap itself around the idea of a damper being "unneeded" to reduce or eliminate a harmonic oscillation since that's precisely what they were invented for and what DW is. (Actually, that article brought up something I also haven't replaced yet which is the panhard rod itself (not the bushings but the rod) as a culprit).
Anyway, this is all to say that although the rig is driving great now I feel like I'm 5k miles of tire wear or a bit of mud stuck to the rim away from another potential DW situation because it's happened before. This includes after the many thousands of dollars of upgrades I just did which is unbelievably frustrating because my primary motivation for doing that was to prevent DW. I've been through
every Death Wobble thread on here and I've done literally
every possible root cause fix and apparently it is still possible on my rig, which is why Thuren's article above appeals to me: I haven't changed the OME steering damper because it feels fine off the truck (or the panhard rod but that
should be OK?!?).
@Delta VS I'm curious as to your thoughts on this. I think what I'd like to do next is install a powerful stabilizer, an IPF one that won't fade just in case that was actually my problem--maybe the new Dobinson's adjustable that you sell because I think that's an IPF?
BUT I'd like to mount the steering damper to the axle and tie rod like a Jeep setup instead of in the factory location which has essentially worthless geometry with the large lift I'm running. Maybe that's unnecessary in 99.9999% of rigs but I'd like to fully prevent this from ever happening again no matter how bad my tires are.
Sorry for the novel but hopefully this helps someone in the future with death wobble.
