SANANTONIO06GT

I know you guys get tired of seeing these and I would use the search if it was working. Basically, go over some bumps in the road, getting this metal to metal sound. I checked the exhaust 3 times, all good and tight. A buddy of mine said maybe the transmission, since it was making a noise backing up in my driveway, which is on a slant. What should I be checking for on the transmission?? I checked the cross brace, its good and secure, other than that, what else is there?? I wish the search was working so I can go thru and get some ideas. If I go to the dealership, they see the exhaust, they are going to say its that.