bad vibration problems

That is generally damaged belts in the steer tires. Insoect the steers or have them inspected by a shop.

 

Common causes of a constant vibration are tires, imbalanced driveshaft, bad dampener, fuel injection system, bearings. Start with the tires and work your way up. Inspect them for broken belts, flatspots, odd wear, etc.

 

A bad dampener is a bad dampener. Once they dry up they will not work again no matter how long anything warms up. The only cure is cganging it.

 

tires seem to look good and they have centrematic balancers. stick shifter bounces up and down with the vibration

 

A broke belt in a tire won't be seen , a tire that is out of balance or out of round will still shake the truck even with balancers. A brake drum that is unbalanced will do the same.