If I buy a 2002 VW Golf, am I going to be making a big mistake?

Price a new transmission! Any 16 year old car with 150k on it could need a new transmission at any time.

used German cars just as some brands of advanced u.s.a. cars become a total money pit once a few years old, insurance totals prove this point if researched , small damage big repair , big cost ! opps, total !

it may not be a big one, but it may turn into an expensive one

My question: Why did you go to your mechanic, and then seek other advice from random people on the internet? If you can't trust your mechanic to tell you the straight truth, time for a new one.

Your mechanic is correct. Those trannies were made to last about 100k miles and they aren't very serviceable. The two I and my bro had wouldn't go into reverse from park unless we put it in drive first, annoying, but they drove ok. I also wouldn't expect the engine to last much longer if it's a gas engine. Diesels, on the other hand, will go forever and burn way less fuel. If that wagon were a diesel, I'd say buy it.

@Auto_Adrenaline I called my mechanic to see what he thought about it before even taking it in, which i never ended up doing. I have been looking for a car for a long time and want to be thorough about my search and find something thats worth my time and money. God forbid I ask for a second opinion on the internet. My question to you would be what's the point of you being on here if not to give other people advice about cars, and why are you coming for a stranger on the internet?