The bell is indeed a stop when retracting. Once it hits the frame, the clutch of the motor will then rachet. A COMMON problem with this type Slide motor system is, the motor/slide ram gear fails and then fails to either run or rachet. This requires a replacement of the telescoping ram and the motor. They usually come as a kit. Just replacing the motor does not always fix this problem. A work around when it fails is simple. There is a manual override either ON the motor or the OEM has used a extension on the motor to beside the area of the Bell. Just manually moving the motor to extend slightly(less than an inch) will now allow the system to function. But, it will fail again in the future. Doug