My 2002 BMW 325i Sedan has 84000 miles on it and the last few thousand of those I'm noticing a bit of a shudder switch from Reverse into Drive. (Auto Steptronic). Seems to happen when it's been parked a while but might be happening all the time. I've been wondering if doing the Transmission Fluid and Filter might address this for me. Car has been 99% reliable for 4 years otherwise (though for some reason it tends to stall if parked outside in torrential rain or automatic car warshes.). Everthing but the oil and wipers, brakes and tires are the originals I think.