My TL220 is suffering from a slow droop in the arms (dropping in height) when shut down or under power without any input. It is very gradual but annoying. There is only 2500 hrs on the machine. There are no signs of any leaks on the lines. I thought is was the seals in the cylinders but doesn't make sense that when the rod retracts into the cylinder, it would still drop as there would be less room for compression. There is a dip in the bucket when elevating the arms indicating there is probably an issue with the self leveling control valve. Has anyone experienced this or would perhaps know what could be the cause? Thanks