Frustrating, Embarrassing and Concerning Noise

I had something similar happened with my last truck. It. Was caused by warned out engine mounts.

 

My vote is pilot bearing/input shaft.

 

Quit eating those truck stop burritos.

 

I had a 2000 F-350 crew cab with a 6spd that did the same as the op describes. Input shaft bearing was the culprit. Aluminum casing made for a symphony of noises from that Trans.

The cab bag theory sounds solid though.

 

Great to hear you got it solved! Volvos seem to be particularly vulnerable to ride height issues. I bought a brand new 1998 VN 420 with an N14 and 18 spd. On my first load it did this growling. Took it back to dealer, mechanic went underneath with a tape measure, and as I watched loosened off the linkage on the air ride valve and set it. It was worse on the trip home! After seeing what he did, I crawled under and went the other way with it. Took a couple tries, but got it. Makes them growl like an old bear when out of whack. Makes me wonder how we got by in the old days with spring ride trucks. They must have been too high when empty, and too low when loaded. Headlights must have been out of whack all the time too. Although with the poor quality sealed beams we had then, it didn't really matter, we couldn't see much anyway.