Just Tranny issues?
 

Hi Guys and Gals! Im new to Audi and the Audi forums but I have a few questions I hope another A6 owner can help with.
First off I just bought a 2000 A6 4.2 Quattro.... Down side is not an hour after I bought this car the problems started to arise...I asked the guy point blank to be honest and tell me what it needs or any issues it had to I could decide if the cost was worth the trouble....The guy was selling it because it was his fathers who no longer drove...OK made sense as the car has 74K on it, and by the looks of it you could tell it wasn't abused, leather was awesome and everything worked....So I thought....
After I started it up and drove off all was peachy, even during the test drive it was fine so I was shocked when I was almost home and at a red light the tranny started to slip in first.....I thought OK may be low on fluid. The next day when I took a closer look I discovered these cars have no dipstick....So on the phone I go to find an Indy shop or a Dealer. I drop it off Yesterday (towed) and I just got a call and this was the prognosis: It has a rear seal leak and the Trans fluid was low...OK I see the dollars trying to fly out of my wallet now...The first thing they want to do is a full trans service....Makes sense I say go ahead and do it; cost, around 400 bucks. 2nd they say if the problem with the slip is solved with the service, well need to address the leak, approx. 600 bucks and the cost is overwhelmingly labor heavy, the parts cheap. They say this should solve the trans issues. SO I paid $1900 for a car I'm now dumping another grand into....
As a prior Alpha owner I understand the cost of repair, but my question is this.....Are these cars prone to have these types of issues? Can I expect this car to turn into a money pit with just 74K miles on it? Hopefully my sig worked but if it doesn't then the car is an 2000 A6 4.2 Quattro with 74K on it.