Duvan and Brian, The reason for the transmission change came after I started getting a vibrating coming from the main rotor system in flight. I got my friend to bring his balancer, and we spent all day trying to get it rebalanced with no luck. After doing some investigation and talking to the factory, it was decided that the upper bearings had worn and lost there pre-load. The old transmission is soon to be shipped back to the factory for detailed tear down. I opted to buy a new transmission, due to time factors, and not knowing if the old one is rebuildable or not. The factory is always fantastic to work with and very helpful. I also opted for the new one due to the fact that they have made some improvements in them in the last 10 years. As of now, the only time life components on my entire helicopter are the 2 oil filters, everything else is on-condition. The current transmission price is around 4k, and the factory is more than happy to sell replacement parts. The only thing that you can run into on the bigger parts is supply. The way the factory tools up for Blades, Rotor heads, Transmissions, engines and gear cases, if they are out of one of the large components, you may have to wait a while until the tool up for those items. I got lucky in the fact that they were out of the main rotor transmissions, but where in the process of building new ones.