05 Rendezvous squeaks and grinds in reverse

My 05 Rendezvous had new tires put on the front only about 3 weeks ago. The rear tires had good tread still so the manager at discount tire said that i could replace only the front tires and it would be ok even on an AWD. Before I took it in for tires, I noticed when driving forward slowly, I could hear a sound from a wheel(s) like a scraping noise. A few days ago, my Rendezvous started making a squeaking sound when backing up like a metallic squeaking that would stop when I put some brake pressure on. Now there a heavy scraping sound when I back up slowly. Does anyone have any suggestions as to what could be causing these sounds? I think it's my wheel bearings... :uhoh:

A quick test to see if it is your wheel bearing would be to jack the car up, get the suspected tire (wheel bearing) off of the ground. Grab the Top and Bottom of the Tire and rock it back and forth. Any "play" (Movement or space for movement, as of mechanical parts) in the motion is usually a good indicator that the wheel bearing is bad. I just replaced wheel bearings on the left side (front and rear) this past weekend. A good wheel bearing will not have any "play". It will be rock solid. My other guess's might be brakes or the rear transmission. Search this forum for problems with rear transmission.

thanks, i think ive got a two problems at the same time. I suspect the wheel bearings are making noise in forward gears because I tried coasting with the gear shifter in neutral and I still got metallic sounds at the same rate as the rpms of the wheels. On the other hand, the squealing in reverse is only when I apply the brakes so I'm fairly sure that sound is the brake pads or rotors.