Q: Concerns and checks before warranty ends at 60k

On a level surface the transmission dipstick after car drove and still on reads half in the margin of where it should be also it is no longer red, more grayish. Should I be concerned? Is it leaking? heard of common place it could, dealer said no leaks or codes. How much should an engine vibrate in engine brake parked? I change regular oil every 6k, putting full synthetic in next time. Drive mostly highways ranging from 80-90 when no traffic. Under warranty already replaced a gasket or seal because it was leaking. What are the odds for more or others to start? When care running there is a high pitched noise that I do not remember when the car was newer (been in the family). Changed fuel pump, maybe helped alittle. It is back. Also is it normal to see slight rev differences in park with AC on?

My car has 57000 miles.
My car has an automatic transmission.