Okay, one last thing: The growling noise is loud from about 20 mph to close to 60 mph, but it kind of goes away after that. I'm not sure if that's just becuase it gets drowned out by other noises, though. It is present under load, but even light load, and practically disappears while coasting.
Does this sound more like pinion bearings or carrier bearings? I'm getting both answers. Also, if I take the axles out, and rotate the pinion by hand, if a pinion bearing is bad, should I be able to feel it?
THanks again for all the help. I'm excited to finally get my hands dirty again!