I have a 2000 chevy with a 454 (7.4)crew cab 2500. It has 36,000 miles but have experienced it using alot of oil. Aprox. 1 quart every 500 to 800 miles. Towing or not towing it still uses oil. The dealership has gone over the truck and has found nothing. They have established an oil review program every 500 miles to review it. They have said that commercial vehicles are not covered by normal oil use in chevy engines. I was hoping to hear that I had a cracked ring or bad bearings or something else but nothing else was said. Has any one had a simular problem or do you thing I maybe getting the shaft. By the way no oil leaks, nor oil blowing from exaust.