Considering a 317?

So my dilemma is, there is a guy near by with a 317 Series two tractor with a decent deck and nice shape overall with one exception. That problem is it vibrates while the engine is smooth I believe it to be the drive shaft after reading alot about it. I have also found two different people selling the shaft with the u joints. Now my question is would this tractor be worth it or should I move on because of other issues the vibration could have caused? Are there any tell tale signs to look out for?
Thanks,
Attila