Jim, there is a magnetized suction screen that needs to be cleaned along with changing the hydrostatic oil
and spin on filter. Its part of the routine servicing of the HST transmission. Details of the suction screen assembly can be found in the operators manual for the 4100HST also. (See pg 75.)
The screen is located under a cover, on the rear transaxle housing at the back of the tractor, just below the pto shaft and above the drawbar. Its held on with two bolts, with a pipeplug in the center for a drain. Oil from the sump is drawn thru that screen by the engine mounted pump that provides for the tractor's hydraulic flow.
The spin on transmission filter protects the closed loop system of the HST's pump, motor, and power steering. It filters the sump oil before its drawn in by the charge pump.
Interestingly, the operator's manual that I have only mentions servicing the transmission oil and filters after every 500 HRS of operation. My trans fluid/ filter was changed out at around 100hrs. The suction screen had some trapped metal shavings on it. Nothing out of the ordinary. Just doin' its job like it should.
Jim, just like you I have additional hydraulic components into the system, including an another cylinder just
for my dump trailer. Two extra gallons were added about 40 hrs ago. I'm almost at the 200 hr mark now. Maybe I should consider another routine maintainance change myself. Couldn't hurt.
DFB
