Death wobble on a ram 1500

Worn parts in the front suspension is my guess. This article is for Jeeps but most everything also applies to your truck. https://www.extremeterrain.com/wrangler-jeep-death-wobble.html

When I was in my teens I used to work for a chicken farm weekends and after school (Yea Cool Ha ha) its how I bought my first car but anyway I drove a worn out farm truck, long wheel base to town to get a full load (abt 3 feet higher than the cab) of feed once a week, which was way more weight than that truck could handle = the shocks bottomed out all the way, tires bellowed out almost flat, at about 40mph if the road leaned to one side the truck would develop a swaying hopping rolling wobble and the more you tried to keep speed the worse it got, but if you hit the brakes it wanted to loose all control and could go anywhere. It was a full fledge farm truck, never should of been on the road or given to someone to drive. The weird thing is it was only 6-7 years old buy lived a life of pure disgrace. Wobble or sway if it gets out of control then it may cause a wreck, this was back when less cars were on the road and I have not thought about it in years but it was bad and times 2-3 of us were in the truck I would just let sway and rock and wobble and hope it made it back for the 20+ miles each way and when we got out we felt like we had been a day on the lake in a boat.

You may need to replace your Bell bearings my truck does the same thing

Sorry ball bearings I've got the same truck and am just trying to save the money to get it fixed