Vibration between 30 - 40 MPH

Like cold tires in the morning before they warm up.

 

I bet you have a bad ujoint and/or work yoke somewhere.

 

860K? On a 3 year old truck, someone did some trailer truckin'. Vibration under load ( acceleration) is almost always bad U-joint.
Anyone here remember "tandem axle hop" between 30-40 mph?

 

Had a cube van with same symptoms, hard shake under acceleration.
It was a very bad u-joint, needles were falling out of cup.

 

My wife and I have ran her pretty hard. But been a great truck. I appreciate the suggestion. I’m gonna have to get it to a shop this weekend. I couldn’t get up under the truck very well. It has all the side skirts and all on it and well frankly I didn’t fit very well.

 

What ended up the problem,?

 

I 2nd the shock comment

I was having an issue with a shake 30-40 on washboard roads
Changed the shocks and it’s all good

Should change them regularly anyway and it’s a cheap item

 

Do we know the outcome?