I was changing the transmission fluid on my girlfriends car over the weekend (a Subaru with 100,000 miles on it). On this particular car, the transmission pan has a drain bolt and a spin on filter that's essentially a small oil filter. This makes it easy to do. Anyway, it still had the original transmission fluid in it, which was dark and smelled funny. I wouldn't say that it necessarily smelled burnt, but I can say I've never smelled anything like it. Anyone here ever come across burnt transmission fluid and can say exactly what it smelled like? Having said that, the only useful thing I have found so far on the internet was a suggestion to take some new transmission fluid to a torch for a while and see what that smells like.