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644D-34 Lull transmission issue

Discussion in 'Forklifts/Telehandlers' started by tractormech, Jul 31, 2018.

  1. tractormech

    tractormech Senior Member

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    Hello all-I'm having an odd issue with a transmission. It's a 11000 series Clark.It's in a Lull that they only made for about two years but I guess that really doesn't matter. It works in beach sand and it's weak pulling in forward low gear but seems plenty strong in reverse. Clark claims that the ratio is the same in forward as reverse but here's what is so odd-on flat hard ground if you put it in forward low and give it full throttle it will haul butt-but in reverse it doesn't go near as fast. We have to back it on the trailer as it struggles terribly in forward.I don't think it's a clutch pack slipping because it's been this way for as long as we've had it (5 years) and as it works in beach sand the clutch would have failed by now. I checked to be sure it wasn't wired wrong to a different gear and it isn't. Anyone seen anything like this? Clark told me it wasn't possible for the ratios to be different but yet the speed is way off. Thanks everyone.
     
  2. tool_king

    tool_king Senior Member

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    Did you take any pressure checks at the test port fittings ?
     
  3. icestationzebra

    icestationzebra Senior Member

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    That machine didn't sell very well. I think part of the issue is that the market wasn't ready for a side engine low boom machine yet. Capacity at full reach is only 150lbs. The engine is only 85hp, and the bevel gears in the 90° and Tee box sap some of that power. Don't turn up the power as I'm surprised you haven't twisted a gearbox shaft yet playing in the sand. Decent little yard machines. ISZ
     
  4. tractormech

    tractormech Senior Member

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    Tool king-Haven't done pressure test yet but got a call it quit going in gear. Went to it and found the 7.5 mini fuse in the circuit board blown...replaced fuse and it would back up but would blow the fuse in forward. Turns out the solenoid for forward shorted out. I borrowed the second gear solenoid and it went in forward but it was real spongy feeling/sounding. I tried to go forward but it wouldn't pull....it tries to move but in the beach sand it's a no go. I pushed it to the street with a skid steer and on asphalt it goes forward real slow. I figure forward is finally gone. I talked to someone else I know who had one and he said his was the same way...first gear forward would fly compared to reverse.He complained about the pulling power too so I guess my issue isn't unique. When I tear it down and look at the gears that will tell the story on the gear ratio.I hope a lower ratio is available as this thing is almost useless as it is.
     
  5. tractormech

    tractormech Senior Member

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  6. tractormech

    tractormech Senior Member

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    It wasn't a big seller for sure. I was told they were struggling financially at the time and were trying to expand into a new niche where full visibility was a requirement but I don't know if that's the case. All of those gearboxes rob power for sure and but surprisingly they haven't grenaded one yet. You are right though...it's okay as a yard machine on hard ground but it is a lightweight to have a 6k lifting capacity. It's like an orphaned stepchild to Lull...no service manual and I finally got a parts book and an electrical schematic. It would probably be a good idea to replace this with something else as
    lull has been discontinued.
     
  7. tool_king

    tool_king Senior Member

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    Would you mind emailing the schematic .Email is tool_king@hotmail.com
    thanks
     
  8. tractormech

    tractormech Senior Member

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    I will...info is hard to come by for this machine.
     
  9. tractormech

    tractormech Senior Member

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    Update-I replaced the second gear solenoid and it went in first gear and off it rolled.According to the Clark tech manual it energizes forward and first clutches only for low gear but when I put second gear solenoid on I noticed it was energized as I slipped it over the spool for second. Weird, I thought....why does second have power? The manual doesn't say if the coils are hot to apply the clutches or power is cut to apply....Anyway,it works again so I'm happy.
     
  10. tractormech

    tractormech Senior Member

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    Another update-got a call that the machine was even weaker in forward than before-went to it with some more info on the transmission-found out that first and second gear solenoids are energized to make it go in first gear forward. Checked voltage and 2nd had 12 volts but first had 4.5 volts. I rigged up some wires and it went right into low gear and pulls great in the sand. Started backtracking and when I got to the shifter I disconnected it and ran a hot wire to the feed terminal and checked voltage on the wires that feed 1st and 2nd gear solenoids...2nd had 12 volts but 1st had 4.5-the contacts in the shifter are bad.
     
  11. laycobeau

    laycobeau Well-Known Member

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    Tulsa Ok. beau.bowlan@lei-corp.com
  12. tractormech

    tractormech Senior Member

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    I don't know for sure-we bought a new one to get going but the plug is wrong.Called the dealer and asked about an adapter harness and they say it called for one-then called back and said it was out of stock and they didn't even have a vendor for it. I can cut the wires and use the old ends but don't want to void the shifter warranty. So either JLG gives me something to keep the warranty or the owner makes the call or I find ends and make a harness. It's aggravating.
     
  13. tractormech

    tractormech Senior Member

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    Do you repair these units?
     
  14. laycobeau

    laycobeau Well-Known Member

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    Occupation:
    Lead electronic technician
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    Tulsa Ok. beau.bowlan@lei-corp.com
  15. laycobeau

    laycobeau Well-Known Member

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    Lead electronic technician
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    Tulsa Ok. beau.bowlan@lei-corp.com
  16. bindian

    bindian Well-Known Member

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    Can you please send an electrical schematic to bindian@hughes.net ?
    Thanks.
    hugs, Brandi