Thank you for the update.

My 3500 has always had a real mild shake motion at highway speeds.

It's been a long time since I owned an HD truck, and since you don't buy 1-ton trucks for the ride necessarily, I figured it was the price you pay for capability.

I had the tires rotated and balanced several times, and it never went away.

Tires are the stock Firestone Transforce AT on 20-inch rims with 23k miles on them.

I finally saved the cash for a nice aggressive Toyo mud terrain in stock size, and after reading your post, I can't wait to see if that shaking goes away.

I realize the M/T will be noisier, and the overall ride quality won't be as smooth, but having that little wiggle/shake motion gone will be heaven.