Ordered the 01 2500 ext. cab in March 00. Was told it will be made in St. Louis or Mexico. Told the dealership if I had a choice make it in Mexico. Was told I don't have a choice. Was made in St. Louis; came in in May of 00. Cummins had "upgraded" the engine to a HO- 245 HP. for 01. The 6th. speed ,I believe, had been out for maybe 2 years. When it first came out there was a shifting problem either between 2nd. & 3rd. or 3rd. and 4th. The problem was fixed when I got mine. Very smooth between all gears,if one shifts into the right gear. Mileage, unloaded, average 21mpg., loaded with 14k average 11mpg down here in the flat lands at speeds of 671/2 mph. Stupid speedodomter is graduated in 21/2 increments. From Loveland to Cheyenne averaging 25mpg unloaded. Must have been the altitude.
Have replaced alternator, starter,"slave" brake, relined brakes, fuel lines, injector pump. Engine has not been into. Burns no oil. Have used Rotella 15w 40 from the beginning.
Caution; if you think there is a fuel line leak be very careful,fuel pressure into the cylinders is 17,400 psi from the injector pump.. Can't be seen. Will penetrate the skin and if it hits you in the face that would be Bad news. Use a piece of cardboard to check around fuel lines.
The Problem; had the truck about 3 months, working a contract job in Southeast Tx. Was driving to work and the truck stopped. Towed to dealership. Lift pump. Was on the 4th. lift pump, counting the original, the first 3 years. Called Cummins and ask them why. They were "shocked" said it was the first time they heard of such a thing. Phunney thing, in 03 or 04 the fuel pump was in the fuel tank. Am on my 5th. lift pump at present, it's a Bosch, must be a good one. Check pressures fore and aft quite often.