[Yosemite Sam]

You don't mention what model tractor you're looking at, without that information it's impossible to answer your question.

If it is a Cub with the Sunstrand transmission it is possible that it has been damaged but I seriously doubt it, if what the owner says is true.

I see morons on ebay and craigslist all the time with Sunstrands for sale from $75.00 to $200.00

A good Sunstrand transmission is worth its weigh in gold, because they are so durable. On the other side of the coin, since they are nearly bulletproof, I almost never sell one because they never go bad.

That said: I've got a dozen of them laying on a shelf that I personally have seen run. I'll sell you however many you want for a very reasonable price.