It is too early to change the tranny fluid. I would not touch the trans fluid till 100k miles. If I was to change the fluid, I would only change it at the dealer and no where else. They call it lifetime for a reason and I would follow their reccomendations. The trans dipstick tube actually has a locking cap on it so you dont attempt to check it. On my new CLS and SLK with the 7 speed, there is not even a dipstick tube. If the fluid is low it will trip a CE light. $269 is reasonable since the fluid alone costs about $100.