This is a 1991 420SEL with 81,000 miles recently aquired and a beautiful car but when shifting into reverse it seems to slam into gear instead of the feel that i get when shifting into drive. Very smooth with the rear end setting down a bit. starting out cold in the morning it shifts well, easy shift and the rear end lifts just a bit. I also think there is more hesitation when shifting into reverse,takes a few seconds. When it worms up after driving it slams into reverse. Would this be a rearend problem or possably a transmission problem?