On front drive models, the belt runs from the engine to the front of the mower and routes to either a pulley on a transmission or an idler pulley on a bracket assembly. In most cases, the belt will be located on the left side of the mower.· On rear drive models, the belt runs from the engine to the rear of the mower and around a pulley on the transmission. In most cases, the transmission pulley is on the left side of the mower.