Well, been over 2 years and nearly 77,000 miles so I thought that I should swap out my serpentine belt before heading to Florida in a couple of weeks. Thought that a "Gatorback" would be a good choice. Unable to find one online, was told that Autozone is the "hot ticket." Well, not in Sandusky Ohio! Called them up, asked for a belt for my 2001 Silverado Duramax 6.6 48 state truck with single alternator. Got a "huh?" "Sorry I got no number - bring in the old one and we'll try and match it." Old one is ON THE TRUCK, my only vehicle!Anybody got a Gatorback number for the 48 state 2001 with single alternator? Thanks!