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Grasshopper owners with weak Hydro units read this !!

Discussion in 'Mechanic and Repair' started by 22R, Feb 4, 2003.

  1. 22R

    22R LawnSite Member
    Posts: 24

    I have a 1996 721D with the 21 horse Kubota diesel. I bought it in 2000 and it had 1600hrs on it. The engine runs great and the machine is still in good shape but the drives were weak. I asked on this site and people in general about rebuilding the gemini transmissions and no one seemed to know how to do it , I was mostly told that I could buy new ones for about 650.00 a side. I was about to do that when I decided to take one apart and see if I could find anything wrong with it. With assistance of 4-H Equipment in Denham Springs, La. I was able to replace some O-rings and back up rings on some pistons and replace the check valve assembly that is attached to the dump valves. It made a big difference in the performance of the machine and I only spent about 150.00 in parts. I only share this cause I was lead to believe that the only fix for the Gemini was to replace the drives. Hope this helps some one else. Later, 22R
  2. bob

    bob LawnSite Platinum Member
    from DE
    Posts: 4,254

    Thats great that you did that. I've never heard of anyone taking a GH hydro apart. When I talk to my local dealer, they act like going into a hydro is taboo. I've got a 1997 & 1999 GH. They both have close to 1500 hours. The 97' had the left hydro replaced last year at the tune of $800. GH makes work manuals for their machines. I bought 2 on eBay. Good luck.
  3. 22R

    22R LawnSite Member
    Posts: 24

    That is kinda the impression I got talking to different people. But it wasn't really hard so unless it all flies apart this spring I'll call it a sucess. Later, 22R
  4. 22R

    22R LawnSite Member
    Posts: 24

    Somebody must have a bad hydro on a hopper to talk about ???
  5. SDlawndawg

    SDlawndawg LawnSite Member
    Posts: 119

    My dealer never ever considers working on the motors. It's easier for them to replace them. If any of you decide to tear a motor apart, contact the tech guys at Grasshopper. They will go through step by step to help you. They have saved me lots of time and headaches.
  6. allenandinga

    allenandinga LawnSite Member
    Posts: 33

    I've never heard of these gemini hydro units everyone is talking about here. Every Grasshopper I've ever seen has hydros made by Eaton just like Snappers do (both machines were designed by the same people BTW). Is this some new unit they're using now or what?
  7. Mowingman

    Mowingman LawnSite Platinum Member
    from Texas
    Posts: 4,664

    The Eaton unit is the Gemini unit. Eaton makes them.:)
  8. allenandinga

    allenandinga LawnSite Member
    Posts: 33

    Ok, now I understand. I knew they were made by Eaton but never heard the Gemini part.

    I can add one thing that will save someone from throwing one of these units away. If you disassemble one of these units, you will find some big ball bearings. DO NOT SWAP THEM AROUND IN THE HOLES! These balls are measured with some type of laser micrometer (can't remember the name of it right now). When you see the measurements written down, there are about 10-12 digits to the right of the decimal point. The balls are fitted in their respective holes to exacting tolerances. If you mix the balls up, when the unit comes up to operating temp the balls will start to stick in their holes causing a loss of pressure and driving problems. Without the machine the factory uses to measure the balls and holes, you would almost never get the balls back in the right hole. I did this very thing a few years ago (mixed up the balls) and then found out you can't do that. Had to put in a box to use it for parts later maybe. To buy a new set of rotors with balls already in the right holes would cost almost as much as the whole hydro unit would. I guess sometimes it doesn't pay to play when you don't know what your playing with.
  9. 22R

    22R LawnSite Member
    Posts: 24

    I was warned about the balls before hand and knew not to mix them up. everthing else was pretty simple to do. Later, 22R
  10. The Lawn Caddy

    The Lawn Caddy LawnSite Member
    Posts: 29

    IS there a seal or o-ring on the output side of the shaft. My left hand wheel has fluid leaking in it. Can it be taken apart aND REPLACED?

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