Shakes Violently over 55-60 mph

[tdereggi]

My 2003 Ram 2500 4x4 crew cab 5.7Hemi Truck drives fine under 50mph on smooth road, But if I try to drive over 55-60 mph or hit bumps on highway, the truck will randomly start shaking violently like a bucking bronco so bad I can barely hold the wheels straight, until I can slow down and get it to side of road. Shaking wont stop until I get almost stopped. When I start moving again, it drives fine while under 50mph. Its extremely unsafe. I havent been able to find the cause.

Note the engine is fine, no engine shake and no engine mount issues.

The problem didnt exist when I first got the truck, but it had quite a bit of steering play, and a few other worn parts. So I decided to do a bunch of suspension and steering upgrades.
Ive performed the following work:

First, I replaced the two peice steering shaft (Dodge OEM, upgraded newer one)
All New Ujoints. (factory maker, I believe AMG and Spicer)
New transfer case
New complete steering linkages and tie rod ends. (after market, moog HD)
All new front ball joints (EMF high quality ones)
New PowerStop rotors and brakes.

Steering still had play, so I continued...
Replaced 4bolt power steering gear w/ larger 6 bolt unit and PS Pump & lines.
(however the Mopar gear came defective with too much play,)
So Replaced PS gear with a RedHead gear. (which fixed the steering play).
The 6bolt gear upgrade also required upgrading to the newer style HD Crossover steering linkages, and HD pitman arm, which I did. I also changed sway bar rubber and end joints.
Also added a steering gear stablizing bar.
After all this, it now has the shake at 60mph problem.

The truck has after market vision warrier 17" rims w/ LT315/70/R17 (35s) Cooper Discoverer AT3 XLT. Truck is lifted, Maybe 2".

I did not change wheel bearings or drive shafts, as they seemed fine. Nor did I mess with differencials, It was a big job replacing ball joints, had to pull it all apart. Nothing is making noises driving below 50mph.

I had gotten a wheel alignment, somewhere in the process. but I'll probably get another wheel alignment just to makes sure, now that everything was complete. One of my front tires is starting to get some uneven spots, so gonna replace my front tires and rebalance them, to see if that helps. But I dont think that would be the main problem.

Anyway, any ideas on what could be causing my shaking? What I missed ?
Or how to troubleshoot finding the problem?

Because problem is at high speed, I wonder if its a shaft balance related thing? A driveshaft to wheel ?

 

[jws123]

Soudns like you have death wobble it can be a pain in th **** alignment needs to be spot on aswell as good tires have had bad tires alone cause it on my jeep. It sounds like you replaced alot in the front end have someone look at it to see if possibly you missed something that has a little play in it try to find a shop that deals with lifted/heavy duty trucks.

 

[rzr6-4]

Welcome to the wonderful world of death wobble, where the steering wheel is but a suggestion.

One of the biggest components is the track bar, which I didn't see any mention of. Thuren, Carli, Core 4x4. Made a world of difference for me.

Also, your tires getting uneven could be a major player as well. My previous set of tires that I just took off, one of them was "chopped", still had tread but uneven wear. That would cause tiny vibrations but that would be enough to initiate DW. Mine got to where it was literally undrivable, until I swapped the front tire with the rear which was in better shape and it went away (temporary fix until I got the new tires ordered).

Definitely get those done, and if it still has issues there are a couple other things you can look for.

 

[Marshall]

rotate tires/ wheel, look close at driveshafts, u joints
have you had it on a hoist and run it with wheels off the ground?

BTW ,if you are getting cupping on a tire, that is where you start to look, new tire will do the same thing if something is not correct. It could be a tire that is coming apart.

 

[Daw14]

I know this is a few months old ,and might have been resolved.
I did not see any mention of shocks , may have been missed or overlooked,but definitely need inspected .
Bad shocks can contribute to tire cupping.