Located inside your door is a "door glass rubber stopper".  This stopper is what keeps your glass from dropping too low into the door channel which would result in breakage of your glass. 
 
When these wear out it will cause your door glass to either drop too low, or get cocked in its channel which can cause the window (door glass) to chatter when rolling it up/down.  These have been discontinued from Chrysler and are getting increasingly difficult to source.  Chrysler part number:  3875997   We only have 6 available (as of the time of this writing).  These are OE factory Mopar.
Price is for Qty 1.   Order the qty you need.