I have a model 20016 that will not self propel. I have changed the wheels because the right hand one was stripped, but now it makes a screeching noise and will not move the wheels. I have had it apart and the belt is really loose but it appears when you engage it tightens up, so I think this is okay. I took the cover off of the transmission and am not sure if the gears are not meshing or if there is a bearing problem. I was going to order a transmission assembly, but have read on hear things about the engine pulley. If anyone can help me figure out what is causing this to not engage the wheels I would appreciate it.

 

Is the transmission pulley turning when you engage it?