Loaded question I know. It always depend on how it was taken care of. Speaking of which, I am amazed at how few used trucks for sale have any maintenance records at all.
2005 Mack CHN613, AC427 Engine, 527,000 miles, Eaton 10 spd, 4.17 gears, 12,000 lb front, 19,000 lbs rears tandem axles...