Rough idle, new to audi.
 

Hi there,
I bought A6 4 wheel dr, 98, 120000 mls, autom. transmition. a month ago. Whoever owned before did no service to a car what so ever, even timing belt wasn't replaced. So I've dumped $3500 already. What bothers me the most is the rough idle, when speed reaches 35 - 40 mph, the whole car shakes when changing the gears,after that everything normalizes.I guess it's transmition. Does it mean that it's going down and I'll have to replace it? Or something minor can be done? Thanx a lot for any advice.