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  1. #1
    RC Racer
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    3rd time out with the truck, lost front wheel drive. :(

    I've not had chance to look at the damage yet, but the front diff is currently the prime suspect.
    I wouldn't have minded so much, but I'm not even driving it hard yet.
    I'll ask for more advice as I strip it down later on tonight.

  2. #2
    RC Racer
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    Iíve been following your build, but canít remember are you running stock motor? What about gearing? Do you hear clicking when you hammer the throttle? If so, thatís a tale tale sign youíve stripped the ring and / or pinion gear in one of the diffs.
    When you soup up a motor people tend to strip gears on the daily. One solution, which Iíve been doing is to shim ring and pinion gears.

    Use Teflon shim (https://www.amainhobbies.com/traxxas...ra7781/p475947 )

    for ring gear behind left carrier bearing.

    Use 2 of these:

    https://www.amazon.com/Axial-Racing-.../dp/B00TKHZAZ4

    on shaft of pinion gear.

    This will tighten up the mesh and slop when housing flexes and get you a little more usage out of your differentials.

  3. #3
    RC Racer
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    All still stock, barring the uprated traxxas servo and dog collar to stop the battery clamps coming undone.
    I've put a Proline body on it, but that doesn't count.

    I'll post up some pictures as I start to strip it down.

  4. #4
    RC Racer
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    And I forgot, thanks for the shimming info, I was going to ask if it needed it.

  5. #5
    RC Racer
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    OK, so the front diff seems to function fine.
    No signs of damage when I've pulled it out, but I've not dismantled the actual diff itself, seems no point.Turn both front wheels together and the center shaft turns.
    Unfortunately the rear wheels and motor don't turn with the shaft.

    I'm guessing this has got to be a shot center diff? The rear wheels still have drive, so I can't think what else it could be.
    Guess it's time to pull the back of the truck off.

  6. #6
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    Quote Originally Posted by Chewbacca 3 View Post
    OK, so the front diff seems to function fine.
    No signs of damage when I've pulled it out, but I've not dismantled the actual diff itself, seems no point.Turn both front wheels together and the center shaft turns.
    Unfortunately the rear wheels and motor don't turn with the shaft.

    I'm guessing this has got to be a shot center diff? The rear wheels still have drive, so I can't think what else it could be.
    Guess it's time to pull the back of the truck off.
    Of course, check the central diff and the pinion in the center shaft.

  7. #7
    RC Racer
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    Yes, or the double spline bit that connects center diff to center aluminum drive shaft snapped (easy fix).

  8. #8
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    Quote Originally Posted by afreek1000 View Post
    Yes, or the double spline bit that connects center diff to center aluminum drive shaft snapped (easy fix).
    Exactly this piece I say.

  9. #9
    RC Racer
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    That actually breaks?
    I was thinking centre shaft or that bit, but was like, nah. They can't be broken, too sturdy.

  10. #10
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    Quote Originally Posted by Chewbacca 3 View Post
    That actually breaks?
    I was thinking centre shaft or that bit, but was like, nah. They can't be broken, too sturdy.
    Nothing is unbreakable in this life.

  11. #11
    RC Racer
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    You guys called it. It's the spline drive connection piece.
    I'm amazed that would snap.
    I'm just hoping it has not taken anything else out as well. How that could break before shredding planetary gears is a concern. I'm half expecting to find more damage when the spares arrive, but I'm not stripping out the center diff if I don't need to.

    Appears you can only get it with a new centre shaft?
    Pt# 7755

  12. #12
    RC Qualifier Flux Capacitor's Avatar
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    Quote Originally Posted by Chewbacca 3 View Post
    You guys called it. It's the spline drive connection piece.
    I'm amazed that would snap.
    I'm just hoping it has not taken anything else out as well. How that could break before shredding planetary gears is a concern. I'm half expecting to find more damage when the spares arrive, but I'm not stripping out the center diff if I don't need to.

    Appears you can only get it with a new centre shaft?
    Pt# 7755
    Yes, that is correct, you can only get it with the purchase of the whole center shaft.

    This is a bit alarming considering you mentioned running stock. I had read of another instance of this sectional spline piece snapping and I'm trying to imagine how these guys that are running powerhouse setups on their 58113 cans and not snapping that piece at all with massive amounts of torque.

    This ultimately makes me question myself about whether or not to actually remove my center HR locker. Something must be happening between the feedback from the Cush Drive Assembly and center differential as opposed to the other two differentials to cause a momentary counter-lockup that snaps that piece in a heartbeat. I ultimately don't think it was user error on your part that caused this.

    I did the counter planetary differential rotations on paper and it seems that a center differential kind of defeats the purpose of the other two differentials. Traxxas claims that the center differential is to ease stress on the drive train and thus eliminated the slipper that was on the previous 6S version trucks.

    However, by my calculations of mass rotation of each component in the drive train, a center differential can be counter productive because it can ultimately have a split second of counter rotation under no load from the motor that is unnecessary and not proportional to the overall direction of the main components and thus result in the snapped center spline insert.

    It is the only explanation that can explain why that piece is snapping when no other drive train damage is present to have caused it. That, and the possibility there was a foul cast when the piece was formed.
    Last edited by Flux Capacitor; 11-10-2020 at 09:33 PM. Reason: Updated.
    Sent from my autonomous device.

  13. #13
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    Quote Originally Posted by Chewbacca 3 View Post
    You guys called it. It's the spline drive connection piece.
    I'm amazed that would snap.
    I'm just hoping it has not taken anything else out as well. How that could break before shredding planetary gears is a concern. I'm half expecting to find more damage when the spares arrive, but I'm not stripping out the center diff if I don't need to.

    Appears you can only get it with a new centre shaft?
    Pt# 7755
    Exactly, only can buy it with a center drive shaft.

  14. #14
    RC Racer
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    So a big shout out to my favourite UK supplier, who have sorted the issue after a few emails and photos, by sending me out the replacement part for free. Glad I bought the truck from them now. I will continue to go there for all my RC needs and can't recommend them enough. I've no clue if they got reimbursed by the Traxxas UK supplier or sorted if themselves, either way, many thanks.
    They were also great with advice via email, before I even got my X-Maxx.

    WHEELSPIN MODELS

    Website

    Hope this isn't against any forum rules, they do sell Traxxas after all.

    Just waiting on the trusty postman with the bits now!

  15. #15
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    Quote Originally Posted by Chewbacca 3 View Post
    So a big shout out to my favourite UK supplier, who have sorted the issue after a few emails and photos, by sending me out the replacement part for free. Glad I bought the truck from them now. I will continue to go there for all my RC needs and can't recommend them enough. I've no clue if they got reimbursed by the Traxxas UK supplier or sorted if themselves, either way, many thanks.
    They were also great with advice via email, before I even got my X-Maxx.

    WHEELSPIN MODELS

    Website

    Hope this isn't against any forum rules, they do sell Traxxas after all.

    Just waiting on the trusty postman with the bits now!
    Excellent mate, very good aftersales support.

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