Transmission/Torque Convertor Problem?

Lately, I've been having a few problems with my 1991 S10 Blazer (4x4). When I shift into reverse, I hear some very loud clanking noises, like grinding gears or something. I also hear these noises sometimes when I turn the wheel. However, these things only seem to happen when the truck is warm, and has been running a while. First thing in the morning, I never hear any of these sounds. My question is, could this be the transmission or the torque convertor?

noises could also be coming form the rear axle, or the front axle or the transfer case