@Lincsdigital perhaps this issue has been solved already, but if not, can I just check that you are using the word “selector” above as a way of describing the code to me, rather than the code actually container the word selector? If it really does container selector, that might be the source of the problem.
If this issue is still active, please could you send me a link to the page where you tried to transition the background -color and height? The code looks like it should work if the selector is correct, but I can only tell so much from looking at code by itself.