# Zero turn mower jerky as heck.



## Country Boy

Have an Ariens Zero turn mower in the shop at work that is dangerously jerky when trying to drive forward. Smooth in reverse. When I was working on it tonight, you'd push the levers forward and within a few feet, the front wheels would be bouncing off the floor and you'd be hanging on for dear life. I checked the fluid levels and they were a bit low, so I topped both transmissions off to the recommended spec. I also replaced the drive belt and checked the pulleys on the transmissions and the engine to be sure they were tight. When I move the unit in reverse, everything seems normal, but in forward, the levers start violently jerking and cause the whole unit to shake.

I took it outside and was driving it around the parking lot, and I noticed that if you are driving on level ground and gently ease it into forward, the unit will drive smoothly. If you start climbing a hill, it will start to jerk again. Darn near flipped it over backwards when trying to climb the hill by the loading dock due to the front end bouncing again. Never had a unit do this before on both sides. I've had loose pulleys and bad belts that caused one side to slip, and I've had leaks that caused one pump to loose oil and suck air, but never both sides evenly and at the exact same time. Seems odd that both transmissions would fail simultaneously. They are Hydro Gear EZT transaxles and the unit is about 6 years old. Transmissions are clean and show no oil leakage, but both were about 1/3 of a quart low. They aren't packed with dirt either, and the cooling fans are in good shape.

I have to talk to Ariens tomorrow about this unit, but I thought I'd see if anyone else has seen this before. You can't always get a straight answer from a manufacturer because they don't want to admit they have problems...


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## farmertim

Is there a limiting valve missing on each side maybe? Seems like a flow control issue to me but then hmmm what would I know?
Clutching at straws without being able to see touch hear and feel.
Hope you get it sorted, it sounds downright risky, you got a seat belt on that thing?


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## Country Boy

Called Ariens Tech on this, was told to tighten all the mounting bolts and see if it made a difference. No change. They were all very tight. I noticed that once the unit started jerking, it seemed like your arms were adding to the jerkiness because you were bouncing around. I pulled the dampeners and found that they were good and tight in reverse, but when you pulled them out, they had about 3/4" of play in them before they would offer any resistance. I ordered new ones, but they won't be in until Wednesday. These dampeners are attached to the control arms, and I noticed that the new units have the dampeners attached to the arm on the transmission instead. Seems that is a better idea because it will prevent slop in the linkage from causing something like this. I'll post back when I get the new dampeners installed and try it out.


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## tractorman14

farmertim said:


> Is there a limiting valve missing on each side maybe? Seems like a flow control issue to me but then hmmm what would I know?
> Clutching at straws without being able it needs adjustments on the linkage which makes it loose and jerky


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## Country Boy

Well, turns out it was a combination of problems. The belt was slipping, so I replaced that before I wrote the OP. That actually seemed to make it more jumpy. I replaced the steering dampeners and that seemed to eliminate the problem. There was just too much play in the dampeners and the jerking of your arms would jerk the levers too easily, causing the jumping of the unit. With the new dampeners installed, the arms move with more resistance, and you don't jerk around anymore. Seems they switched to a different dampener as the part number on the new ones was different than the old. Perhaps they had problems with failures on them after all....


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## farmertim

Reminds me of my Bobcat operating days you work the machine with revs flat out and operate the levers "with confidence" if you operate them without being deliberate they will rock and jerk all over the place.
glad you got it sorted out it is a quick way to lose your lunch.


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## dan26

I know this is an old thread but I found it when I did a search as I have the same problem. Finally after talking to Ariens I found the solution e eryone should know.
Ariens has a problem with the frame breaking right near the hydro drives, which allows the drives to move causing the erratic movement. It sucks, but Ariens knows it is a common problem as they do have repair kits for some models, such as my 1540.
Anyways, if you searched for jerk Ariens zero turns and found this thread, besides what the op wrote make sure you check for a broken frame.


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