Shaking/vibration

Hello my name is Dave.

The first suspect with a speed specific vibration is the tires, I would begin with having the tires rotated and balanced. There are a few other things that can give us some clues to the problem. First question is does the steering wheel shake when this happens? If it does then here is our tutorial on steering wheel shake:

https://www.2carpros.com/articles/steering-wheel-shakes-when-accelerating-or-braking

If you can perform these steps and let us know the results we will be happy to guide you further and thank you for using 2CarPros!

No it's more like the whole truck starts vibrating. now there seems to be a very high pitch noise coming from the motor.

This sounds like a tire issue like one of them is coming apart. I would jack up each end of the car (one at a time) and roll the tires to looks for imperfections. here is a guide to help you:

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

Please run down this guide and report back.