Eaton 18spd Intermittent Problem

[MSPOIRIER]

UPDATE: Removed the rear range cylinder cover and replaced the large outer and small inner Oring on the end of the piston along with a new cover gasket bit could not change the small inner. (Due to the Aux section needing to be removed to pull out the cylinder on "9 series") took for a test drive but I still got a quick range grind on a shift while all the other shifts were fine. I would say no change but I am going to keep running it as long as it does not get worse and try to pull the AUX at the end of the season. I added a couple more pumps of 75w90 and hope for the best. Any other suggestions would be appreciated but we may need to open it up at some point for this one!