Vibrations.... of the bad kind

[apstguy]

See if you guys can help me on this - If I go high way speeds, at a point where I push the accelerator pedel down, the whole truck starts to vibrate. Very bad! It is scary going 75 and the truck starts to shake like it will fall apart and deposit you all over the pavement.

I have ballenced all the wheels, and probably need to get it alligned. My shocks are shot, but I don't think that is it. My greatest fear is it is my transmission It has started to shift "weird" (such a scientific description huh?). The engine and transmission both have 132,000 original miles on it.

At least I know the truck as a whole is solid. My brief encounter with a nasty woman driving an Intergra left me traveling sideways with my brakes locked up on the freeway. I'm still a little bitter.