Sinister Diesel 01-05 GM Duramax 6.6L LB7/LLY Welded Water PumpProper heat management from the cooling system is crucial on modified engines when you want trouble free and reliable performance. The factory Duramax water pump is known to slip under load and can serious problems and serious repair bills on modified high horsepower applications. This updated design is a drop in replacement for the factory water pump and uses precision TIG welds to secure both the impeller and pump gear to the shaft. If your 2001