Firstly I would like say that I am big fan of Kitchen Aid appliance, unfortunately the ice cream maker is the most frustrating and disappointing appliance.  The parts are tricky to put on and if you do not get the right fit, when you turn it on it starts to jolt, which if you are not careful, can cause the small metal ends on the Drive Assembly to come out of place.  Secondly if the mix is too thick this will also cause the parts to come out of place and then it is impossible to continue as the Dasher will not fit properly in the bowl.  Wha I find the most frustrating is that you cannot stop during the churnning process to stir in any of the mixture that is at the top of the bowl as again this will cause the parts to come out of place.