2013 Peterbilt 384

What's the application?
Cab is sister to 386. Pretty durable with no major issues. Keep the brake pedal pivot lubed and free. In the north the road salt will freeze it up in a hurry. Keep stuff off the dash, anything drops down the defrost will get lodged in the mode door and hang it up.

Trans should be straight forward just keep it serviced with fluid and filters.

Engine will not tolerate extended periods of idle. Clean the EGR system and intake crossdrillings annually. Keep up on the DPF cleanings or just put a reman on when it's full. Also will not tolerate running low on coolant. EGR cooler will crack in a heartbeat, and if run long enough leaking you'll be buying an engine. If taken care of they can reach 500k without major issues. Dont expect a powerhouse in a full size truck. If it feels lacking, buy bigger.