Hi guy's, hope you can give me some advise on a Cat D6 5R that I am looking to buy. The engine starts and runs fine, clutch seams to be engaging properly [ owner say's clutch has been adjusted, and is worn out ] but friction plates engage tightly and transmission shaft comes up to speed. We cannot get the Cat to move with engine running-trans in 1st gear-forward / reverse arm in ether position-clutch engaged-hyd. operating and blade lifted. We have pushed it forward and backwards with a front end loader and it rolls easily. Any information would help. Owner has had this Cat since 1970.