I hear a humming sound in my cab when I hit 35 mph could that be some type of bearings going out. Oh and I cant find the pcv valve on this thing

Pcv normally is located in valve cover or intake manifold on any engine. they generally have a hose going to manifold source and are like 3/8" diameter hose. The vibration could be exhaust. there was a rpm where they liked to vibrate because of their solid assembly of the parts and the engine's output resonance, more expensive vehicles have a resonator, or a muffler that acts like a stomach. but they are often german. You can isolate noise or harshness sometimes by adding tire psi, then trying it. for an experiment. Bearing noise may increase and decrease when you slalom left and right. on a country road. Driveshaft related noise or fell can often by on accelleration at your specified speed.

(or fell ?) I did not type that

( by on accelleration?) No, often be on accelleration .....excuse me I must have two middle fingers on that hand