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Simplicity 4211 Hydro Bucking Problem


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Need help on a problem with my Simplicity 4211 with Hydrostatic transmisson! Am experiencing very uneven speed with the engine at high RPMs and the transmission set at a low to medium forward speed. Bucking is so bad at times that the front wheels almost lift off the ground. At low engine RPM or full speed ahead, problem appears to go away. Not sure about reserve, don't use it enough to notice. Other symptom is that the speed level pushes back with strong pressure when climbing hills, have to drive with my hand on it to keep moving forward at times. Started noticing the problem months ago, mostly when the tractor was just getting started on its chores for the day. Has gotten much worse recently. Have replaced the drive belt so do not believe that it is the problem. Being in the great state of Washington, which has no dealers close to home at this point, have to confess to using standard automatic transmission fluid to top off over the last few years. Any hydrostatic drive experts out there? Any suggestions? Will I be able to get parts and do major work myself? Thanks! Al Figler alf1725@aol.com
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It probably has never had the filter or fluid changed si i would change the filter and fluid. The fluid is Automatic transmission fluid. This & $1.00 might get you a small Coffee Maynard aka/UCD
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Hi, If your fluid level is OK, I would suspect that the top anchor bolt in the transmission case is missing. More likely the boss for this bolt is broken out of the case. This usually starts when one of the u-bolts that hold the rear axle housing on each side breaks or comes loose. This lets the axle housing move. On the top of the gear reduction case is a boss that anchors the top of the case, the bolt is ahead of the battery and to the left of center of the frame going down through the frame and into the boss. Usually the movement of the axles breaks the case at this point. This is in the gear case that that the hydro pump bolts to. When the axle reacts to the torque at the axle, the case rotates, the linkage is fixed. When the unit moves it moves the arm in the hydro, violent reaction. Sorry to be a bearer of bad news, I hope it is just the bolt out. Good luck Al Eden
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AL I have a 4211 that i am restoring, i think i will go check to make sure everything is tight in the areas you mensioned>>> thanks
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Think we can close this one off! Inspected the tractor, bolts on top of the transmission case were all in place so I decided that after 16+ years, it was time to change to fluid as Maynard suggested. Checked the parts book, no filter to clean. While under the rear, realized that the both bolts that hold the angle iron to the frame were missing on the left side! A quick trip to the local NAPA store and the new bolts were in place. Took another look at the transmission bolts which were now sticking up. Torqued them to the required 20 ft-lbs. Al Eden, you were spot on! Thanks to all, really appreciated the help. Cannot believe how much better the machine runs with new fluid and all the bolts in place.
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Hi, Thought I might mention when you change the oil in these Eaton hydro pumps, On the top and bottom there is a bolt head for a plug. Before starting clean very well [pressure washer works well] around the top of the unit. After removing the bottom plug, remove the cap fron the overflow reservoir and the oil will drain. After all is drained, install the bottom plug, then remove the top plug. Pour the oil in the reservoir and the oil will run in until it gets up to the top plug. Next install the top plug and fill to the level mark on the reservoir. By removing the top plug you let the oil flow in, if isn't removed the pump will air lock and it can take hours to get the oil in. The alternative is to remove the reservoir, which is left hand thread and pour the oil in that hole. Then you can screw the reservoir in and top it off. Just be sure it is spotlessly clean so no dirt gets in. Good luck, Al Eden PS. If the trans is gettin weak and leaky, you can try putting like 15W50 or 20w50 SYNTHETIC oil in. I haven't done it, but have 3 customers that have and have got another coulple of years out of a weak pump.
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