OK, friend has a '00 4Runner V6, auto 4X4 SR5 with 150,000 miles on the clock. At about 60,000 miles it started making a chirping noise from the pass. front under the hood when moving. Been taken to the stealership four times since to decode the issue. The dealer can't replicate it, replaced pass heat shilds, sound is still there. Wheel bearing were all checked they are all good. The sound happens from 3 mph on. more pronoced on deceleration. Does NOT happen when standing still and reving engine through rpm range. DOES happen when the truck is rolling with automatic in neutral and reving the engine? I was thinking fan clutch, maybe rear driveshaft U-joints??