I am sure there could be many reasons for this problem but let me know what you think. At about 80 to 100 KM/h the truck shakes. I can feel it through the steering wheel and it shakes bad enough for me to not be able to have a coffee in the cup holder as it spills. I am taking it into the shop this week but anyone have this problem? what could it be?
Thanks for your input. By the way it is a 2006 Ram 1500 4wheel.

 

Sometimes warped rotors, but that shows usually on braking. My first guess is out-of-balance or out-of-round tire.

 

Well, you start with tire balancing, then alignment, then you look at the tie rods and ball joints. Could also be the hub or even the drive shaft could be out of balance.

When you start with balancing, make sure the place "Road Force" balances the tires, a standard balance often doesn't do the trick on 5000# plus vehicles. Seen many a guy get a balance then have a shop soak him for big time jack on ball joints and tie rods to only find out IT WAS a tire issue and a road force balance woulda fixed the problem...

 

Rotate the tires and see if it changes characteristics at all. Check u-joints as well, is there a big 'clunk' when you put the truck in gear? When it's jacked up for the tire rotation check the wheels for any play.