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Rear diff issue?

Discussion in 'Newbie Q & A' started by Btngu2, Aug 13, 2016.

  1. Btngu2

    Btngu2 Active Member

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    I am extremely new to rc. I purchased what he said, was an ax10 scorpion artr. I am having 2 issues. The first one, is one of the rear wheels will not pull under stress. The other, is it will take spells and stop moving forward or reverse, but will still steer. If I let off the trigger and press it again, it will move another 3 feet or so and stop like you let off the trigger. I did try to rebind with no change. Any help is appreciated.
     
  2. scalemadness

    scalemadness Studio Forums Elite
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    The rear wheel not pulling is strange perhaps it is rounded where it slides into the diff locker or the wheel hex is missing a pin or the hex in the wheel is stripped as for the moving and stopping maybe its a loose/bad connection are you running nimh batteries or lipo?
     
  3. Btngu2

    Btngu2 Active Member

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    Thank you for the reply. I have tried a 2s and an nimh as well with the same results. The light on the esc will still flash when the trigger is held, but it's a slower flash. Without throttle movement, the light goes completely off. Its an ae5.
     
  4. scalemadness

    scalemadness Studio Forums Elite
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    It is also possible your brushed motor is on its way out with a dead spot which would explain stopping then going again which is basically the brush not making a connection with the commutator in the motor if you have a spare motor try replacing it or pick up a cheap replacement motor and try it to see if the problem goes away i think the motor is the issue though
     
  5. Btngu2

    Btngu2 Active Member

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    Thank you for the reply. I did a few test, and I don't think it's the motor, but I did order a new one for 18 bucks off eBay. It will run for exactly 3 seconds, no matter where the throttle is, or if it's in a bind. Using a multimeter, I checked the power on the motor lead. It goes to around 8 volts at full throttle, then straight to zero after 3 seconds. Could it be a bad receiver? But I can turn the wheels while it won't move.
     
  6. scalemadness

    scalemadness Studio Forums Elite
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    No doesnt sound like a reciever issue it could be the esc but motors can jam up or lose gain electrical contact so a different motor is your cheapest test you could try putting the esc plug into your recievers steering port and see if it does the same thing
     
  7. Btngu2

    Btngu2 Active Member

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    Ok, so I took the esc plug and moved it to the steering port. Turn the steering wheel to go forward and reverse, still same results, go for 3 seconds then stop. But, when I switched the plugs back and hooked up the battery, the truck was running forward and wouldn't stop without hitting reverse! Unhooked the battery and then reconnected it, got it back to running for 3 seconds.
     
  8. Btngu2

    Btngu2 Active Member

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    The issue with the wheel not pulling, is inside the diff. What is on the inside that would cause one wheel to slip under pressure?
     
    #8 Btngu2, Aug 14, 2016
    Last edited: Aug 14, 2016
  9. Btngu2

    Btngu2 Active Member

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    Sorry about the 3 repost, not sure what happened.
     
    #9 Btngu2, Aug 14, 2016
    Last edited: Aug 14, 2016
  10. scalemadness

    scalemadness Studio Forums Elite
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    Take apart the rear diff the axles go into a locker in the center section the axle should be rectangular flat on the inside end going into the locker the locker is a female hole shaped the same should be mild play when inserted into the locker assembly but it is possible it is worn to the point the axle can spin in the locker make sure the wheel hex fits snugly in the wheel as well a stripped hex could also be the issue what radio are you using? Make sure all expos and subtrims are centered or at zero then try to recalibrate your esc and see if that affects your throttle issue
     
  11. Btngu2

    Btngu2 Active Member

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    Ok thanks. I can turn the wheels with my hand and it just feels like it's worn plastic. I can watch the axle turn when I turn the wheels with my hand. On the radio, I'm using the ax3.
     
  12. Btngu2

    Btngu2 Active Member

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    UPDATE.... Bought a used esc from a buddy, and it fixed the run for 3 seconds problem. Another question I have, will scx10 diffs work on this rig? Or at least the inner parts? I'm finding it a little difficult to find ax10 scorpion parts. Is there a forum on this site dedicated to ax models?
     
  13. scalemadness

    scalemadness Studio Forums Elite
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    Yes the ax10 axles are identical to the scx10 the scx10 and ax10 use the same running gear just different frames just make sure you get scx10 parts not scx102 parts
     
  14. Btngu2

    Btngu2 Active Member

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    Thanks a lot! Are the scorpions worth fixing, or should I buy a newer version crawler? Like I said, I'm very new, but so far it's something I want to get into. I also just purchased a running traxxas e maxx for a good deal, it just needs a lower control arm and batteries.
     
  15. scalemadness

    scalemadness Studio Forums Elite
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    The ax10 is a good crawler its not a scale crawler but a great truck the transmission differentials are the exact same as an scx10 but uses a different frame i would keep it fix what needs fixing and if you enjoy it then make your move and get yourself another crawler like an scx10 1 or 2 or even a vaterra ascender
     
  16. lout

    lout Studio Forums Elite
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    I would stick with what you have. The base guts of what you have has been the back bone of the SCX10 and the scale truck scene. Just upgrade as you break things.

    Things to take note of and be expected to replace.

    1. The diff lockers in an AX10 are aluminium and will wear out over time. Replace these with the SCX10 heavy duty diff locker when they fail (sounds like they have failed already so replace the front as well)

    2. The input shaft and pinion is a two piece design and can be replaced by a one piece heavy duty version if you experience problems with these. I have yet to have mine fail, but I know that my diff locks are wearing out :D

    3. The stock drive shaft has a hole down the centre that allows access to the screw that bolts the universal onto the end of it. This hole allows the shaft to eventually collapse. If you can find a piece of plastic rod or sprue from an old kit fill the hole top to bottom. Will make your drive shafts last. I'm on my second set as I didn't put the sprue down far enough.

    4. Transmission. There are three gears in the transmission, the top small gear is metal already and doesn't need to be replaced. The middle gear or idler is plastic and will need to be replaced as you wil strip it. The output gear I can't recall but I think is plastic. But see next point on the output gear

    5. OUtput gear on the transmission for the AX10 has soft grey metal output shafts and I have had mine tear apart. I replaced these and the output gear with a one piece from RObinson Racing Products. Others will recommend getting some with a hole all the way through but the AX-10 doesn't have that.

    Now this looks like a whole lot of problens. It isn't, it is more a list of what I have found running an AX-10 drive train. My rig is much much heavier than an SCX-10 let alone an AX10 so I will be putting more force on the driveline so I have found issues sooner.

    So, run it till it breaks and replace/upgrade what you need to, or save for those items that you know you will need to replace in the future and then along with a set of new bearings and some grease do a maintainence job one weekend and replace everything before the fun stops and then you will know that as far as the driveline goes it's all good.

    The other good thing about these parts is that your LHS or favourite online hobby shop will stock them. If. You do have issues trying to find bits, just ask and one of us will be able to point you in the right direction.
     
    Btngu2 and darkside0914 like this.
  17. Tim S

    Tim S Studio Forums Elite
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    I'm having rear diff issues in my wraith. Been using axials HD bevel gears. The diff is well lubed, shimmed for full mesh without binding, and has new bearings. Today the 3rd set of gears wore out to skippy town. What are my alternatives, who makes great/tough diff gears?
     
  18. lout

    lout Studio Forums Elite
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    Personally I would be looking to see if RRP made a set. But my second immediate thought after that was "what did Dave Jr. put in the Black Widow?" From memory I believe they were Vanquish.
     
    Btngu2 likes this.
  19. Tim S

    Tim S Studio Forums Elite
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    Good question. Thanks. I'll check out RRP. Been on Vanquishs site but can't find diff ring&bevel they themselves manufacture
     
  20. darkside0914

    darkside0914 Studio Forums Elite
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    you could try extra speed on ebay, they make a set of all steel gears that I have tried and failed to damage, and when I say all steel I mean even the locker housing is steel.
     
    Tim S likes this.

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