Well maintained. . HA HA HA HA HA roflmao!!!! I personally know a dolly madison mechanic 2 bays over from my shop. You would not believe what those drivers do to those trucks. He deals with 4bt and 6. 5 chevy all the time as well as various gassers. Interestingly, no powerstrokes. Anyhow, they have drivers keep going with zero oil pressure, no antifreeze, gas in tank, flat tires, etc, etc, etc. Ive seen three brand new 6. 5 replaces at less than 10k cause blown radiator hose and driver wanted to finish route before he turned the truck in.
That being said, he has fewer 4bt problems but I think its more because they have fewer 4bt than 6. 5 on the road. They also run older trucks and replace engines as needed.