Ok here is a good one for you guys, death wobble with a bit of a twist... I have 1998 Pathfinder SE 4x4 5speed, 175k miles. Bought the truck a little over a year ago and keep it stored in La Paz, BCS, Mexico. I never really witness the death wobble symptoms but the whole rear end in the thing felt really loose so I've replace all the bushing and or actual arms themselves on the upper and lower control arms. It tightened things up significantly. About 500 miles ago I brought down some new rancho shocks for the rear and slapped those on myself, again improved handling on the lovely roads down here. Still no wobble. 

So here is the weird part, driving out of La Paz yesterday I notice for the first time what I think is pretty classic wobble...1) at highway speed if I lay on the accelerator as if to pass it feels like the rear of the truck has been hit by a gust of wind, then settles down. If I let off the accelerator if bumps back the other way. 2) also at highway speed hitting bumps or dips it feels like it wants to get pretty loose.

One thing happened in town that I'm suspicious is not a coincidence but I can't logically figure out the connection. Monsoon conditions in town, flooding sewers and mayhem about to ensue. I was driving in about a foot of water(with 4x4engaged just in case) in heavy traffic creeping into town. Sensing things were about to get worse I took an opportunity to throw a quick u turn and jump on the outgoing side of the road which was high and just wet. Mid turn nothing much happened but a reminder that I was in 4wd, that jerky steering sensation. I completed my turn and dropped back into 2wd after straightening out, and got out of dodge. A few minutes later I was at highway speed and noticed it for the first time. Is there a chance that turn on wet but not slick pavement busted something internally? Like in the rear diff? I should note the diff has always been kindof loud on this truck and seems to have more slap than I've seen in other rigs.
Thanks for your time and look forward to hearing input.

Panhard bar since you've hit the other 4, also check the front suspension as well