555A hydraulic fluid leaking into transmission

[Ashinkl]

I have been loosing hydraulic fluid for a while and just kept adding to it. The loader stopped moving in forward gear when it gets hot so I decided to change the transmission fluid. I was expecting to drain 13.5 gallons but instead drained about 25 gallons. Hydraulic fluid is obviously leaking to the transmission. I removed the transmission driven hydraulic pump to replace the seal in the pump; however, John Deere can’t tell me what the part number is for the seal. The serial number doesn’t pull up anything for them to find the part? There is also a seal in the transmission case where the hydraulic pump mounts. Is there anyone that can give me some direction? I was thinking of just removing the seals and taking the to NAPA to match them up with something they may have.

[Jim B]

Welcome to the Boards.

Do you have the Technical and Operator's manuals for your machine?

You can access the parts catalog (PC1889) for your 555A online for free, below is a link to it. Look in the loader section for the loader hydraulic pump. There are two pumps shown, based on crawler serial number. I don't understand John Deere (guessing you mean your dealer?) not being able to find a part number. You are using a JD construction equipment dealer, right? The shaft seal appears to be the same part number for both from what I find. The question would be is there wear enough in the pump that it needs a full rebuild to hold a seal for long. Worn shaft, bushings, housing, etc. will lead to short seal life.

Are you using JD Hy Gard fluid or a JD J20C rated UTHF in all compartments except your engine? Straight hydraulic oil can damage your transmission and steering clutches if it gets to the transmission.

https://partscatalog.deere.com/jdrc/nav ... ment/17654

[Ashinkl]

I cleaned the pump up and it has CESSNA 24500 on the housing. I can’t find just the seal; however there is a rebuild kit for the pump. I was planning on putting hy-guard transmission fluid back into the transmission. Should I also use the hy-guard for the hydraulics? Hopefully I haven’t already messed up the transmission forward drive clutches. It would go forward when the fluid was cold and would stop moving after the fluid got hot. It would still go in reverse when hot.

[Jim B]

I will be very surprised if your Operator's Manual does not specify Hy Gard or equivalent for the hydraulics. I would use it regardless with the possibility of the hydraulic oil getting into the transmission.