Caterpillar 6N3641 Pulley

6N3641 is a Caterpillar belt-drive pulley named Pulley Tightener with three grooves, engineered for CAT equipment. This OEM replacement part maintains the belt tension in the drive system by riding in the tensioner assembly and guiding the belt across a three-groove pulley. Caterpillar catalogs list 6N3641 as a Pulley Tightener and tie it to an extensive range of machine models, including 631D, 631E, 631G, 633E II, 637D, 637E, 637G, 639D, 651E, 657E, 69D, 769C, 769D, 771C, 771D, 773B, 773D, 773E, 773F, 773G, 773G LRC, 773G OEM, 775B, 775D, 775E, 775F, 775G, 775G LRC, 775G OEM, and 834B. In service, the 6N3641 pulley-tensioner plays a key role in maintaining proper belt wrap around the three grooves, helping prevent belt slip and uneven wear on the drive belt that powers accessories such as alternators and hydraulic pumps. As with other Cat tensioner components, it’s designed to fit the corresponding drive geometry and belt profile used by those models, supporting reliable operation in demanding construction and mining environments.