pro8cess

When I slow down from say 20mph to a stop I get a vibration in the truck I'm not sure where this is coming from front or rear feels like the front. It also ocurrs when turning. I've checked the wheel bearings,CV'sm, and u-joints they are all fine. I believe the vibration when turning is coming from the tires because they are a little nobby on the outside edges when I rotated them the vibration and sound dampered a little. I don't understand the vibration when slowing down any suggestions? I took it to Toyota dealership cause no other shops or I can figure this out. Toyota repositioned the pitman arm and adle arm to correct specs as they were new and put on worngly but the vibration is still there they say its the tires! I really don't think it's the tires but nothing sounds broken or feels broken. I had the full chassis lubed by toyota at the same time so my fluids are all new and the vibration feels the same. Could it be the front or rear differential? drive lines? Brakes? I'm confused any help is appreciated