I bet this will test the hydraulic gurus A trackdrive motor wouldn't go into fast, the machine would give a bit of a lerch and remain in slow on one side only. I had a crew working on site so I couldn't stop so kept the machine working in slow until the job was completed then sent into the shop. On arrival I checked the plantery hub which was chockers with hyd oil so have striped the complete track drive. I found the remains of a spring in the motor which looks like the type used in a shaft seal and the only seal of this type is between the motor and plantery gearbox. Removed the through shaft and bearing and bugger me no seal, not even any remains apart from a small peice about 5mm long in the bearing. Iv'e been trying to figure what the heck happend, has the motor over pressuised the casedrain destroying the seal, then jamming the fast speed piston and if so why? This motor is on a closed loop curcuit and only the casedrain is filtered. The 2 speed comes off the control block and is T to each motor, the other motor works fine. The only other thing of note is for the very first time I fitted Balwin filters ( always used Donaldson as fitted from new) about 100hrs ago and the blocked filter warning would come on when the oil was cold but go out when warm.Any enlightenment will be greatfully recivied. PS This motor and gearbox has done approx 700hrs since recon.
What make and model of motor? Have you checked the case drain filter for material? The hub seals are not designed for pressure, so if it wasn't leaving a slug trail of gear/hydro I doubt case pressure was high enough to damage the shaft seal. As a really wild guess I would say wrong seal installed, came apart and bits of it jammed the swash plate somehow. Further investigation required.
The drive assembly is Nabtesco GM 11, similiar to GM9 used in excavators. There was no external leakage. The missing seal was between the motor and gearbox. The swash plate, lens plate and rotating group survived. I am stumped how a seal can pass through a bearing inclueding a spring. The bearing wasn't badly damaged, just enough warrant replacing. All the debries went into the hydraulics and the gearbox was clean. My thinking is the case drain has over pressurizied, but why? Both motors and hubs were serviced by the same world renoned company.
Famous places make mistakes too.... I am not familiar with the Nabtescos but typically those seals have a steel skeleton so it's basically not possible for it to escape without destroying stuff. The seal lip maybe, and the spring can easily come out during installation if care is not taken. Might want to pop the other side open for inspection of the seal there just for insurance. Are these drives on a dumper?
Hy-Dash come out of the same factory in Japan and are fitted in a forestry mulcher. The steel cage has been chewed up to.