I've been working like crazy and haven't had time to put my thoughts together, but I have a moment, and the energy now- at the same time even!

Eddy: The transmission only makes noise when it's driving. Sitting still, in neutral, clutch in or out makes no more difference than it ever has. If it weren't for the fact that the bad noises stop in 4th, I'd think it was the transfer case (although we never hear of those dying like this).

What freaks me out about this is that lubrication is being lost each time I park or drive on an incline. It's the only thing that makes sense, and yet at the same time it makes no sense at all- why would the fluid level still be normal?

I'm thinking about dumping the fluid and replacing it with ATF to see if I get that lubrication back. It might be a waste of money though and I surely don't want to waste money I barely have. Any advisements on this? Thanks.

I am probably overthinking this, but that's what I tend to do on stuff like this. It just doesn't make sense to me, and that might be because I don't know enough about it. Hence all the questions.