1998 Volvo V70 servicing transmissioin

I have had this V70 for 3 years the first mechanics I took it to were certified Swedish Volvo mechanics. When I ask about the trans they said don't worry about it cause I don't have to do anything. Last week I called the service dept. At Culver City Volvo and asked the same question and again I got the same answer. Now I want you guys to tell me why this transmission doesn't need to be flushed and serviced as all other cars I have owned. I keep the maintenance up on the car and with the high mileage use a synthetic oil. I would hate to have to buy a new transmission because I neglected this wonderful machine.