i have a 2001 duramax diesel and sometimes when i start it up the starter motor cluth slips and does not turn over the engine then i turn the key again and it starts right up. i replaced the starter motor and did not cure it is very fustrating because it only does it maybe a couple of times a month then does not do it for ages it seems very random i was thinking it may be a damaged ring gear has anyone had this similar problem ? thanks