I have an 02 Rubicon and it has rescently started to make a zipping grinding sound on steep hills and the will not continue to go up. It acts just like it has a belt and is slipping which i know is not the case.This problem only starts after ive been riding for about an hour.Any suggestions.

 

have you been using an engine oil with "Moly" in it? If so, perhaps the wet clutch is starting to slip?...........Tass