I'm just a maintenance tech here, so I'm not completely sure of all the practices in rebuilding the units, but I'm sure some of the bearings and other parts in the transmissions are costly, and anything that is in good shape and can be re-used will save the consumer money. We don't replace every piece of the transmission, or it would be a new transmission, and would cost accordingly. Whose to say we can't determine if a bearing is good or not?
Anyway, we've found a company that builds bearing testing machines using ultra-sonics and we have an appointment for them to pay us a visit, so problem solved. Thanks for the help though.