My newly aquired 81 300SD with 240,000 miles has shifting issues now that it is cold here in Ohio. The 3-4 shift has a second or two of flare until you get the tranny fully warmed up-10 to 15 miles.After the trany is warmed up it shifts very well.Also, at any temp when shifting into reverse it hesitates a few seconds and then goes into gear in a somewhat harsh manner. The only part I have replaced so far in conjunction with the tranny were the two small vacume arms on top of the valve cover. Do I have an issue or is this the norm? This is my first older Benz diesel.