Hi Andy,
1. I agree the first noise is the throw-out bearing, and I hear mine all the time under the same conditions, no worries IMO.
2. This "Whirl/Growl" is changing (getting quiter) as the countershaft increases speed (Some multiple of the wheel speed, in fact the R&P ratio
. So I would suspect one of the three countershaft bearings, but hard to say which from the driver's seat.
3. Lift off the gas, sounds like countershaft bearing as you mention.
4. One of the two mainshaft bearings for sure. As you engage gears, especially progessively to lower gears the mainshaft speeds up, which coordinates with the sound change you mention.
I would say the trans is wearing overall, but I think it is not "worn out", just showing signs of age. Unless of course these noises started abruptly as of late.
If it was abrupt, and I know this may sound crazy, but I would consider checking your snap-ring, easy to do, and hopefully just for routine check .
HTH,
LarryB
