Another thing to look for is fraying of the belt on one edge. If you see fraying on an inside edge of the belt, it usually means a bearing is going bad in one of the components, and is putting more load on one side of the belt. A misaligned accessory will do the same thing.
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99 2500 QC longbox, SLT, 4x4, 24V Cummins, 5 spd, 3. 55 LSD
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99 2500 QC longbox, SLT, 4x4, 24V Cummins, 5 spd, 3. 55 LSD