MY 2000 DII 140K, new firestione tires, stock size.
I'll give the short version. I had a steering gear box failure so I replaced it with a remanufactured one.
I have always had a slight "death wobble" so I took the chance to replace the panhard bushings at the same time. Also new EMU steering stabilizer.
The wobble is now worse than anything it has ever had before. In addition there is a clunk anytime the suspension flexes.
I retorqued the panhard bolts and it helped but is still there, still bad.
I also adjusted the slack out of the gear box, still there.
I rechecked all the bolts in everything that I touched and they are all tight.
Ball joints seem tight
There does not seem to be any play in the steering linkage(tie rods, pitman etc...)
So, a couple of questions;
do panhard bushings come in different firmness?
Would poly bushing be better or worse?
Could the radius arm bushings be the root cause of the wobble to begin with?

 

What speeds are you getting these wobbles?

 

At 140K, you could easily have warn tie rod ends, warn out radius arm bushings or a bad rebuilt gear box which is kind of common.

 

It is always set off by hitting a bump in the road, usually around 30-50mph. The wobble stops when I slow down to around 30. It will also go away if I go into a curve (ie. side load the axle)
I wish now that I had not changed the bushings and the gear box at the same time. (makes trouble shooting a little more difficult)
However, I keep going back to the panhard bushings. Mainly because the wobble got better for awhile after re-torque.
As for the tie rods and the rest of the steering components, they no doubt have mileage on them. But when the truck is on stands I can't get any play in the steering system.
I may try a different set of panhard bushings, then go on to the radius arms.
The radius arm bushings DO NOT look like fun to replace!!!

Does anyone have any experience with the powerflex urethane bushings?

 

They are not, but if there is any movement in any of the 6 bushings, you do need to replace them.

 

Any thoughts on the urethane bushings? I was looking at the powerflex

 

I've used powerflex in my S60R without complaint, I'm just not a poly bush fan.

 

I used them in my 66 Mustang. VERY solid and long life, but they do like to squeak if given a chance. A bit of lube makes it go away.

 

Sounds like panhard rod bushs or tie rods to me. I'm actually replacing mine this afternoon. Terrafirma HD steering bars w/ grease able ends and Terrafirma adj panhard rod.

 

So today I checked EVERYTHING AGAIN. The Passenger panhard bushing is loose in the rod. I can move the rod OVER the bushings. When I replaced them I pressed out the old ones and put some anti-sieze on the new ones (mistake) and they pressed in. I ordered some powerflex urethane bushings today. They have the top hat design so hopefully even if the O.D. is not exact they wont allow the rod to move. If this doesnt fix it then its on to tie rods then the dreaded radius arms.