Good day. I have a Saab 93 2002 Turbo 2.0. My gears change smooth When in Drive Mode. When I have to reverse the car I push my accelerator resulting in revving the car before it goes backwards. It was explained that if the transmission fluid is low it can be the problem. I checked my dipstick for the level and it seemed to me that it was fine however what bothers me a lot it had a black colour and smell like normal oil. Does the Engin oil and transmission oil differ from each other.