Air in transmission?

Discussion in 'Mechanic and Repair' started by tbilltubbs, Jun 10, 2004.

  1. tbilltubbs

    tbilltubbs LawnSite Member
    Messages: 12

    How do you purge a transaxle? Hydrogear transaxle - took it apart to reinstall one axle. Drained transaxle and refilled with new oil. Now the machine only runs at about 1/2 speed. Anyone have any experiance with this?


  2. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    You should jack up the drive wheels and run it in gear at idle for about 10 minutes for purge the system. Keep a close eye on the fluid level. At least the is what I have been told by Ferris when dealing with there machines. You need to say what kind of machine this is on. It seems that every manufacturer will have a differance way to do it. Have you though that it may be in the linkage when you put it back in?
  3. beransfixitinc

    beransfixitinc LawnSite Senior Member
    Messages: 592

    We are a HydroGear dealer. I tend to think that air in the system would cause the transmission to be jerky, as the air bubbles make their way through the system. Could possibly be the linkage.
    To purge a hydro gear system, lift the unit so that the drive wheels are off the ground. Engage the hydrostatic release lever (as if you were wanting to freewheel the unit), run the engine about half throttle. Move the directional control slowly from neutral to reverse, then slowly to forward, and then back to neutral. Now, disengage the hydrostatic release (as if you were going to drive the unit) and repeat the process slowly, neutral to reverse, to forward, and then back to neutral.

    Repeat this as needed to purge air from the system. Also, ensure that you refilled your unit to proper level.

    Hope this helps.
  4. tbilltubbs

    tbilltubbs LawnSite Member
    Messages: 12

    Thanks for the replies guys. I'll try that this afternoon, and will post results.

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