Hydrostat issues

[JCS49]

I just purchased a used Simplicity Prestige garden tractor with the suspension with shock absorbers front and rear. On rougher ground the transmission surges and I can feel the control pedal go up and down slightly. I suspect that since the frame goes up and down and the speed control mechanism is mounted on the tractor frame and the transmission is mounted on the swing arms that do not move relative to the frame the control arm gets shifted slightly causing the surging. If that is correct ,how is this remedied? Thanks, jcs.

 

[mechanic mark]

Post Simplicity Model Number xxxxxxx, example 2690814, sticker will be located on frame or plate at backside of tractor. Also post number of hours on tractor & Tuff Torque transaxle model number located on sticker at backside of transaxle, example K72. If terrain is not level slow down on pedal but always mow at full throttle. I'll get back to you after you post model numbers & I take a look see at Manuals, thanks, Mark

 

[JCS49]

Thanks Mark for the reply.. The Simplicity Prestige tractor model is 2691129 with a K72H transaxle with diff lock and has 800 hours on it. I changed the transmission oil and filter hoping that would solve the surging issue. It did not. I have been studying the parts listing from Simplicity. The operators manual is exactly like the paper one I got with the tractor, so no help there. I even called the Simplicity help line without much success. Looking at the transmission service group in the parts manual, .#0034 on the lower front kind of looks like a filter or screen but it doesn't say so in the parts listing. Any guidance there? Also item #0170 in the control linkage group shows a spring hooked up to a spacer bushing type thing but it doesn't show the where other end of the spring hooks to. My tractor does not have that spring and it could be that it was lost or taken off. I did an experiment and took off the shocks on the back end of the tractor and installed heavy strap iron in their place so that the transaxle and the frame are rigid together so there is no longer separate movement of the two. Stopped the surging but it makes for a rougher ride. Surely there is a remedy other than disabling the rear suspension system. Any suggestions from anyone in the know would be appreciated. Thanks again, Jay.