Originally Posted by treerootCO
On the Jeeps, the most common cause is the panhard rod mount on the frame side gets worn out (after a little wheeling). There are quite a few videos that show that factory stock has issues though.
This was the issue I had on my 80 - not so much a worn out mount but an under-tightened bolt instead. The result was the same, and the death wobble was severe. Once I got the bolt tightened to spec, I haven't seen it since. But this is not relevant for an FJ40 discussion...
Data point: My 40 has a pretty severe case of Cruiser lean, but I don't have any death wobble to speak of. Other than a very slight shutter around 30mph (which I think is pinion related), I can hit pretty much any speed on my 40 without feeling like the steering is off. It wanders and there's a bit of bump steer, but nothing shaky. OME springs and shocks and OME steering stabilizer - all about 5 years old.