Our 420 E Direct Drive transmission had been over filled with 10 W Hydraulic oil. We thought that was why it was intermittently leaking (a lot) from the top of the transmission. The transmission temperature is normal while working. We drained and filled it with the correct amount of 30 W transmission oil. We still have a large intermittent leak from the top of the transmission. It leaks while running and continues to leak for a while after it is shut down. We think it might be a pressure relief value. Has anyone seen a leak similar to this? Does any one know what this transmission pressure should be while running? .
There are 8 different models of 420E. You're going to have to give a Serial Number to help look up technical information.