In December of 2009, my Silverado diesel required a new belt tensioner and pulley assembly since the original had finally worn out after 8 years and nearly 100,000 miles of service. Yesterday I had the very same parts replaced for the second time in about 32,000 miles and about 20 months of driving. The cost was about 175.00. My disappointment wasn't so much with the repair as the brevity of the length of service of the parts and the fact that the parts only gave 32% of the service the originals did. No one stands behind their parts anymore. Glad it wasn't a camshaft or a main bearing.