Swap out the damaged or cracked flex plate in your 2001-2004 Chevy/GMC 6.6L LB7 Duramax. Over time flex plates can become cracked causing it to vibrate. Symptoms of a cracked flex plate can include clunking sounds or a grinding noise while the engine is running. A flex plate can crack or fail due to an out of balance engine/torque converter or from bolts that were not torqued to the proper specifications or in the proper sequence. The ring gear teeth can also wear rapidly or break off due to a bad starter, failure to use starter shims (where required), or engaging the starter when the engine is running. An engine that makes noise when starting can also be an indication of either a starter failure or broken teeth on your flex plate. The flex plate is a metal disc used to connect the engine to the torque converter. They are used on vehicles with an automatic transmission, as opposed to a flywheel that is normally used with a manual transmission. Flex plates are typically lighter and thinner than flywheels. A flex plate consists of two parts, the flex-plate and ring gear. Steel stock-style replacements are available or upgraded billet versions that are SFI 29.1 certified for competition use. Shop all the top manufacturers such as ATS Diesel, BD-Powers, Diesel Site, DPC, Hays, Revmax, Sun Coast Converters, Valair, and more!