Ok, here is my experience with my truck a '0.5 CDT, should be the same. It is stock, used to tow and as a daily driver. At 154+k I began to have slip in 1st gear and 1-2 stumble. Talked to transmission guy and was told in was going. As we had a big trip coming up in Oct. I had it rebuilt in Sept. with heavy duty parts at the same price as a factory reman. with stock parts. I never worried about what, if or what ever with the trans, but when it showed signs of being a little different then I had it looked into. My perspective is that nothing in absolutely fail safe for ever. I have experience with multi-million dollar machines and they fail at times when least expected. Just be aware of how it is operating and be proactive when you see or feel the signs of something not right or different just like you do with your body. RV on.