乱挡是手扶拖拉机经常发生的故障之一。排除手扶拖拉机乱挡故障，通常是在拆掉牵引框或变速箱盖后进行。这样，不但费时费劲，而且单独一个人很难完成。下面介绍一种排除手扶拖拉机乱挡故障的简易方法。 　　以工农— 12型手扶拖拉机为例，挡位板上的定位槽呈“工”字型。Ⅲ挡 Unblocking is one of the most common problems with walking tractors. Troubleshoot strayed tractors, usually after removing the tow frame or the gearbox cover. In this way, not only time-consuming and difficult to complete alone. Here is an easy way to troubleshoot a tractor jamming problem. Taking the worker-peasant-12 type walking tractor as an example, the positioning groove on the gear plate is in the shape of “worker”. Ⅲ block