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John Deere 770A - Recently Purchased - Gear Change Query

Discussion in 'Motor Graders' started by Adda, Sep 13, 2017.

  1. Adda

    Adda Member

    Joined:
    Mar 29, 2013
    Messages:
    7
    Occupation:
    Farming
    Location:
    Australia
    Previous owner mentioned that gear change cable may need adjusting. Had fitted a new cable and may need adjusting.
    After checking cable adjustment seems to be fine. Gear positions on lever seem to line up with gear positions on transmission. Second fourth and sixth gear seem to be missing – no drive in second fourth and sixth gear. There is no drive in second and fourth in reverse. What could be the problem??

    Many thanks for considering this question.

    Adda
     
  2. gary808

    gary808 Well-Known Member

    Joined:
    Oct 8, 2009
    Messages:
    72
    Occupation:
    operator,maintanence ,fabricator
    Location:
    hawaii
    Sounds like you lost the clutches that are used to make those gears. What does the trans pressure read when your in those gears? I would deffinetly recommend buying the jd service books / manuals.
     
  3. Delmer

    Delmer Senior Member

    Joined:
    Jan 4, 2013
    Messages:
    4,157
    Location:
    WI
    Yep, B2 is activated in all of those gears and not in any of the other gears. Sorry.

    The technical manual to repair the transmission is a component manual, I think. The main technical "operation and test" will have the diagnostics for the transmission, but not transmission overhaul.

    Have you changed the filter and checked the screen? That won't help, but what you find in the screen and filter will tell you a little about what's up.
     
  4. wsw

    wsw Well-Known Member

    Joined:
    Jan 28, 2011
    Messages:
    122
    Location:
    ontario Canada
    It has been yrs since I done a trans in an A model but you have lost a clutch, you can pressure tap most clutches externally