Hello all, I need some help with a John Deere 550B dozer. The owner states that a while ago the hydraulics stopped working and the transmission is overfull of fluid. For some reason all the hydraulic fluid gets pumped into the transmission after about 15 minutes of running it. Then he has to drain the transmission and refill the hydraulic tank to run the blade. He says that a while ago one of the pumps on the underside was replaced and I have the belly pan off to confirm this. Could one of the pumps be bad and pumping out the snout into the transmission? Or is there some seal out between the transmission and hydraulics somewhere? I'm kind of at a loss of what to check and don't want to tear into the transmission if I don't have to. It still runs and drives fine. Any help would be very much appreciated.
If your pumps are driven by the transmission then yes they can pass oil through the shaft seal and into the transmission.
Update, drained all the fluid and pulled both pumps from the underside of the transmission. The one that runs the transmission was rebuilt and is working just fine but the other one that runs the hydraulics had the front seal pushed out when I pulled it. I decided to crack the pump open to look at it and found the "E" seals are chewed up and shot. Its leaking past those seals and pushing it out the front spline shaft directly into the transmission. Called John Deere and they said its obsolete and not available so I have some feelers out for a new pump from Eaton, Part # 25502-LSE. The original is a Cessna pump 25502-LAC and they were bought out by Eaton Hydraulics.
I have 550 b also had replace pump 8 years ago there was 3 left in country bought one was like 2500 bucks. Hopefully it last or dozer is scrap I guess if this one craps on me. Transmission still leaks from somewhere little bit,is there an additive to add to help remedy leak?
I'm not that familiar with the JD550B but I've owned 3 JD450's a B a C and now own an E and all three had/have a separate pump for the hydraulics that runs from a shaft bolted onto the front of the crank shaft, the hydraulic pump sits under the radiator, the blade operation is totally free of the transmission and only requires that the engine runs and is connected via the shaft. Are the 550B's that much different than the 450's?
Yep. Completely different animal. Nope.