Happy new year, Scotty! I have a 2011 Chevy Express LWB 3500, that I bought from a Chevrolet dealer in 2020. The van was priorly military owned, and that had a lot to do with the confidence of my purchase. It's almost meticulous. The problem I'm experiencing is the death wobble at 50 mph. It's not before or after, but only at 50. The steering wheel shakes violently, cargo flies off the seats, my passengers and myself grab ahold and pray for the best, and I am busy trying to get off the road until the shaking subsides...which is usually successful at around 40 mph. I've replaced the idler arm, pitman arm, sway bar bushings on the frame, and just got a front end alignment. The guy there confirmed that the front end is tight. I've watched a hundred videos, been on countless blogs, and nobody knows what this phenomenon is. Do you have any insight? I'd love to hear it! Thanks, Charlie (and tons of other dudes)
confirmed that the front end is tight
well, he wasn't thorough enough. Try a different shop and make sure they check everything. Balljoint, bearings, tie rod ends, wheel balance, everything.
here's something you can do yourself in the meantime. Swap the front wheels to the back and see if anything changes.
It's also possible the frame or suspension components are bent, and often alignment guys aren't the sharpest. Sometimes you just have to get a second opinion at a better equipped, and staffed, shop.
Look for torn boots on your tie rods, tie rod ends, as well as your upper and lower ball joints. Replace any that are tearing.
Jack up the van and give the wheels a good tugging on. You might use a tire iron for extra leverage and push/pull at the 9-3 o'clock and 12-6 o-clock positions. The wheel should be completely solid when you try to pull on it. If there's any give at all, try to figure out what's causing it. Taking the wheel off and prying on the hub itself with the same technique can help see what's moving.
Since it only happens at one speed, your tires may be out of balance. 50 MPH is usually where unbalanced tires start acting up. Do as @mmj says and rotate the two tires from the front to the back axle. I had a similar sensation in my truck a few months ago that got really bad over 70 MPH. Turned out my upper ball joints were pretty shot. The right one was almost seized and the left was pretty loose.
check your u joints, not with a big screwdriver test. I had a problem that was only at about that speed after new tires and wheels. After swapping them around no change, checked the u-joints. Normally they go bad across from each other, one at rearend had just one end bad. Only way to tell was to remove it. Just a coincident that it showed up getting new tires and custom wheels.
A violently shaking steering wheel typically means it's something in the front end.
Scotty was digging deep that day
Indeed