Mine always chirps, but it chirps even more if iv'e been running for many hours ( 15 to 20 hours) non stop, that cummins just doesn't what to stop pullin. It never wants to stop. It just keeps going and going and going. It's kinda a major event to shut her down . It's like the cummins telling us thier not done for the day, please give me more to pull, lets not stop!!!
No chirping or complaining from the powerstrokes when they get shut down, they just want to rest at the end of the day. They must be really tired? Makes sense doesn't it!