If you come to a slow slow speed with brakes applied on a down hill can you hear/feel the change in speed in the vibration...aka the slower you go the slower the vibration is...then its most likely rotors (well im betting its rotors from the description)


If you feel it in the pedal not the steering wheel most likely rotors....very easy to overheat rotors on a truck this size, when i bought mine it needed rotors badly...but when i replaced them it was all brand new brake stuff (still replaced it all and kept the pads as spares)
All it takes to warp rotors is getting them hot while stopping for a light and then sitting at the light with the brake on 1 time 1 stop....race cars are the same and is why when you get off track you never put on your parking brake always just let her sit.

if the steering wheel is shacking most likely have something unbalanced...though if the rotors get really bad you can feel it in the steering wheel.

Replaced my stabilzer over the weekend, very easy job and the replacment part is VERY cheap.