Bad Vibrations under my dash/Gear shifter

Hauling a load of wood the other day...Next day the truck is vibrating as I move threw the gears. I take it in for the 200000 mile tune. I would like to get another 100000 miler out of her. The machanice tells me I my have warped my drive line? I dont think I have a transmission problem...but maybey a universail joint problem. I would like to get the fix right the first time and not chase a lot of loose ends. I should have my tires rotated, but I sont think thats it. I getting most of my vibrations under the dash, shifting up, and down. It settles down when I settle into almost any speed. Any ideas would be appreceated. Thanks

 

I belive I have tracked to a drive line problem.