John Deere 555A leaking hydraulic oil into the transmission housing

[Benzcrawler]

Hello all I have a John Deere 555A I fill the hydraulic reservoir to half way in the hydraulic reservoir sight glass, within 10 minutes of run time the hydraulic reservoir sight glass is not showing any level. The transmission housing dip stick level increases. Based on this I suspect that the hydraulic system pump that is mounted on the transmission housing is leaking into the transmission housing due to a failed shaft seal in the hydraulic oil pump. Please let me know if this is sound reasoning, or if there is some other component that could be allowing hydraulic oil to be flowing into the transmission case at an accelerated rate.

[Jim B]

Welcome to the Boards.

Hydraulic pump seal gone bad is the most likely scenario based on your description. That is the only place the two come together I believe.

I replied to the original post, you made about this on the Early Models Board, the other day.