I have an '09 LTZ with 3.9 engine and 4 speed auto transmission. I am at 134k miles now, bought the car new. I have changed transmission fluid and filter every 45K miles so far. No issues with the transmission yet, but I am worried about longevity of these as they are not the most robust units out there. The car resale value has depreciated to the point where it is cheaper just to drive it until failure and then throw it away or maybe install a rebuilt transmission? How many miles can I expect out of the original transmission assuming fairly conservative driving habits?