Yesterday i was driving along going up a fairly steep hill in the dark. I was traveling about 10-15 mph i believe and though i was in D2. so without looking i switch the gears trying to find just the normal drive and mistakenly threw the car in reverse, the car stopped fairly quickly and i didnt seem to hear any grinding or anything. Have i just shortened the life of my transmission or caused any damage? how long to they usually last in an E30?