Just another thoughty here.... maybe you should chock the front wheels, stick the trans in neutral, shut down the engine, turn the park brake off (& ignore the warning beep for 20 seconds or so), then raise the rear wheel juuust off the ground, and gently spin it by hand. :dontknow: While you're doing that, get down close to each of the pulleys in turn, & watch/listen for the noise you're chasing. Doing this might help locate exactly where the noise is coming from, and it could also highlight where it's NOT coming from too!! :lecturef_smilie:
And while you're at it, you might also want to check the rear drive cog for looseness & the rear wheel bearings for stiffness &/or noises - they've been known to wear out & the wheel bearings will eventually seize.... And while you're down there, very carefully inspect the tread of the rear tire for any 'embedded objects' too - maybe just a small rock stuck in the tread, but I've had a customer who was adamant that one of his 4WD rear wheel bearings was gone 'cos it's clicking whenever the truck moves' only I discovered a BIG roofing type Tek screw embedded in that particular tire tread - took that out, patched the hole, voila, the noise was gone!! Bloke still insisted that I had to've done the wheel bearing, cos 'he'd definitely recognise the difference in the noise & it just hadta be the bearing - it COULDN'T POSSIBLY have just been a Tek screw in the tire!!' :shocked:
Noises on vehicles can be very deceiving, not only in what they sound like they might be, but also in where they sound like they're coming from!! Good Luck! :thumbup: