The other day I noticed a large puddle of transmission oil under my 2000 K3500, it’s never leaked before and it’s been sitting for a couple weeks so I’m not sure when the puddle appeared. I got under it and it appeared to be leaking from the gasket for the pan. I go to check the oil level and it shows that it’s way over filled. I’m pretty sure I had checked that earlier this year and it was at the right level so I was really confused. I drained some oil until it showed right at the “cold” level on the dipstick. I took it for a drive to get it up to temp and check the level when hot and the transmission was not acting right...had to rev to get going, not shifting right, etc, so i turned around and got home. Check the oil and now it showed super low...below even the cold oil level. So I added oil back in. I also noticed a faint smell of burnt oil once I got home. What the hell is going on?

Just for more information it’s a 454 with a 4L80E.

Edit: Just to clarify I checked the oil with the truck running but not up to temp initially.

Lowered K3500 for your time (not mine)