I have a 2008 chevy malibu ltz, just had it serviced at chevy dealer and 3 weeks later my car started making all kinds of noise and transmission was shifting hard and would not go in reverse. I have had no other problems and I get it serviced on time every time. What can cause it to be 2.5 quarts low? I've had it checked for leaks and none was found I park on concrete every day and i have never seen any fluid on ground. I had it checked for radiator problems and there was none. Im assuming that the chevy dealer did not check my fluid because I don't understand how it got that low that fast if they did check it, but they sure checked off on list that it was good. What can cause it to be low if there are no leaks?