Did you service your swivel *****?

 

Problem solved. The day before heading out on the Canada trip I decided to go through the entire steering system part by part and look for gremlins.

I found:

Loose splines on the steering shaft where it attaches to the input side of the steering box. The shaft could be wiggled around on the splines. It was basically hanging on by a thread, hiding under the foil heat shield out of sight.

Panhard bar mounting bolt on the axle side loose.

Steering box mounting bolts *not deadly loose* but easily took a lot more ft-lbs of torque.



Not sure which issue or combination of issues killed the vibrations, but this just confirms what should be obvious: make sure the parts that turn the car are REALLY tight!

 

When you have death wobble you should go through the "system" as a whole.
A little play in lots of things can combine to give pretty significant death wobble. Hence the link provided in post #2.

 

"Loose splines on the steering shaft where it attaches to the input side of the steering box. The shaft could be wiggled around on the splines. It was basically hanging on by a thread, hiding under the foil heat shield out of sight."

i found the u joints on the steering shaft were worn with my RRC, same thing they are hidden so you dont notice them.

 

Yeah, that should have been the first thing I did. I took for granted the idea that everything steering box back should be tight, since I'd personally replaced the box upon purchasing this truck.

Yep it's definitely and out of sight out of mind thing. Mine still had about an inch worth of splines on the input shaft of the steering box but that is a split joint with a compression bolt. And that bolt could be loosened with my bare hand!

 

Make sure the mount for that loose panhard bolt isn't wallowed out.

 

It seemed tight at first, but with a long handled wrench took a few extra turns. Should I worry and check it out or just wait till the next set of bushings go in? (soon)

 

I'd pop the nut off and see if the hole is oval.