Accessory drive belt tensioner

The automatic tensioner that keeps the accessory drive belt tight — the belt that runs the alternator, the water-pump drive, the power steering and the air conditioning. It is a spring-loaded arm with a pulley, and when the spring tires or the pulley bearing dries out the belt starts to slip, squeal, or in the worst case get thrown off. Replace it with the belt, not after it: the access is the same and a new belt on a weak tensioner is a job half done. The specialist page states that Bando makes the original tensioner for these trucks and sells it under its own label, and the catalogue lists an alternate Mitsubishi number alongside this one, so let the parts counter cross-reference rather than insisting on a single number. The number and the fitment come from a Montero specialist's catalogue and an independent parts catalogue, cited below — good evidence for what a part number is and what it fits, and not factory literature, so read every figure on this page as the catalogue's claim rather than as a service-manual specification.