3-Point Hitch GC2300 3PTH Creep- Looking for a fix

[JDKu]

My tractor has around 700 hours. For the last 100 hours, the 3 PTH creeps down at random times. I often carry the rototiller for ballast when working with the FEL. It's a bit annoying as I need to be constantly lifting the 3PTH. Sometimes it will stay up for many minutes. Other times it will creep down in under a minute. If I adjust the "screw" thing that controls rate of descent and try to lock the 3PTH in the upper position, it doesn't seem to make any difference i.e. creep still happens. Does anyone know how to fix this?

 

[jeepcj7]

1. If it leaks down when the "screw thing" is turned in then the seal or check ball on the "screw thing" is leaking
2. The seals on the internal lift cylinder are leaking.
3. The 3 point lever is not fully returning to the neutral position - fiddle with it a little when the tiller is lifted up in the air.