 You don't want to take off on a trip and that little differential has been seeping for the last year, and then you're taking off and you're very low in differential fluid because you can cause some damage there. So have those fluids checked or check them yourself. If it's due for an oil change, make sure you have the oil change performed, and that is a great time to go ahead and say, hey, just look the car over, see if anything's due.