This smooth idler pulley fits 2001-2010 Duramax including LB7, LLY, LBZ, and LMM. Each engine takes two pulleys. Listing is for one piece. Genuine GM/AC Delco parts. “I find that the bearings are getting pretty dry feeling in the 90,000 mile range. This is a good time to do both idlers, tensioner, and belt. Replace before they fail.” -JK
