As an owner of an '04 2500HD, I've dealt with many of the same repair issues as detailed here. I also can't decide when enough is enough. My truck is used mainly for towing our fiver and not a lot the rest of the time. With the 8.1 engine and 8 mpg, it's not a vehicle you tend to want to drive to get ice cream. Hence it's on vacation when we re towing is when we have the problems. So it gets very tedious and nerve racking every time we go on vacation knowing that something is probably going to break. Nothing so far has been catastrophic, other than the brake lines bursting. But that was luckily in my driveway. Shudder to think if I was towing what the outcome of that would of been... Replaced rear half of transfer case due to Pump rub - yep; rotted brake, transmission,gas lines replaced - yep; Oxygen sensor replaced - yep; manifold bolts replaced - yep; too many rusted rotars and brake pads to count - yep; blower blend door acutator(twice)- yep; both front hubs replaced - yep. All on a truck with less than 70,000 miles. I wish I knew when enough is enough. I think I'm getting close.