when I accelerate in my lifted Silverado I hear a chatering whistle howl noise when I give it gas. is this the pinion bearing or carear bearing?

Hard to say. If you jack up the truck you should be able to tell. The backlash gives some natural play between the ring and pinion. Try to turn the drive shaft and wheels, where ever it does move is your problem. Due to the crush sleeve pre-loading the pinion may be hard to move but you should be able to tell the difference between that and bearing damage.

check your rear differential pan for seal leak. im betting its the pressure inside the differential thats making the noise also why the under spray of the oil on the bed.