i just bought a bone stock 2001 2500 reg cab 2wd cummins with 267,200 miles. Has an auto tranny and owner said he just did a total front end rebuild. Has never had any type of hitch in bed, and never pulled anything. Just used it as a fleet vehicle for his company. Is there anything I need to look out for and check reguarly? Any mods I can do to increase the engine and trannys life? This is my first diesel so I am new. Any advice would be greatly appreciated.