So what, exactly, was the part where you felt you got fleeced? Did they replace the tranny without your permission? If so, they can't just do that.
Did they charge you the price of a new tranny? Or labor for the rebuild? If I have downtime, I rebuild engines to be installed later. Still costs the same, but takes less of the customer's downtime.
I guess the equipment business is a little different, but we use plenty of rebuilt 3rd party stuff. We always give the customer the option, though. It's cheaper than new, quicker than us rebuilding, and takes some of the liability off of us.
I'd say there's no way to know the quality of the rebuild, just based on the fact that it was third party (if that's the case). The stuff I see at my dealership ranges from better than factory quality to how the hell's that thing staying together?
I can't speak for the place you went to, but if we installed something similar and it failed, we'd replace it no questions asked. If it failed twice, we'd go with a different vendor for the part, probably OEM.
Hope this helps,
Steve.