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  1. #1
    RC poster
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    Dec 2019
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    Exclamation Self-Righting -- Part failure >5 Mins

    Hi,

    So I just registered, and this is my first post. My wife and I excitedly purchased the E-Revo VXL (2.0) on Saturday 12/28 in the evening. We had done quite a bit of reading (we felt like) and picked it up from our LHS. We read manuals, charged batteries, and did more research before going out to run it Sunday morning.

    My wife was having a blast! It flipped driving over a tractor rut on our place, and we were excited to see the "self-right" happen. Excitement turned to horror quickly. In seconds it went from rocking, to sounding like a bag of marbles in a hurricane.

    I've pulled the simple items apart and believe I have found the problem. (Spoiler: center diff feels seized). The spur gear has wear markings, but didn't melt and didn't lose a tooth (good sign). The gear on the motor shaft is pristine. Inside the transmission, the gears look ok, but this is where our marbles sound is coming from. Perhaps a bearing isn't 100%? Can't tell, but it does spin.
    The center diff I have not opened. I don't want to void any warranty and I'm not sure if Traxxas will help with warranty at all (their book sounds like they sure dont have to). I've read good stuff on this forum, and will call tomorrow if recommended.

    Noise doesn't come from spinning spur.
    Front spins via shaft, no sound.
    Rear spins via shaft, no sound.
    When all hooked up wheels don't spin under load - do spin off load.
    Center diff, shafts won't turn under considerable twist (hand). Likely spider gears in pieces in there...

    Any help, advice, or just "bummer bro, but it's worth it!" would be nice right now.
    The wife's grin when this thing was running was awesome. She loved it!

    P.S. title should have said less than 5 minutes...its late. Sorry.
    Last edited by Nowcows; 12-30-2019 at 02:14 AM. Reason: Title should have been <5 mins

  2. #2
    RC Qualifier Panther6834's Avatar
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    Jan 2019
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    SF Bay Area
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    970
    When I got back into RC a year ago, after a 35+ year "draught", I was trying to decide between the Slash & Rustler 4x4s. In the end, one of the primary reason I decided on the Rusty was because of the self-rightening function. As cool as it is, it is also one of the ABSOLUTE WORST things you can ever do. Even though I no longer user it, I've still had several people WARN me against ever using it. I'm not trying to say anything bad about Traxxas, but coming up with this feature was one of the DUMBEST things they're probably ever done. If you take work others, they will warn you, as well - do NOT use the self-rightening function, as you WILL damage your vehicle.

    ~ More peace, love, laughter & kindness would make the world a MUCH better place
    ~ Love, laughter & kindness makes the world better

  3. #3
    RC Champion Acidic01's Avatar
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    Welcome. Glad you enjoyed the car while it was working.

    The self righting feature is very hard on the cars. It will find the weakest point from motor to wheels. Only use I'd you want to break something unfortunately .

    Can you post a vid of the sound?

    Did you run engine with spur gear or pionion removed, or so that they are not engage by pulling motor away. This checks motor.

    On the center diff. It will be very hard to move the 2 shafts by hand. Much harder than front or rear diffs. You can pop it open and look,. But my guess is it is not inside the center diff with the 4 spider gears. As fluid is 20Mil weight and like putty. I don't think you would get that kind of sound out if it ring gear can break

    If a part did fail give Traxxas a call. Good chance they may send a replacement. Since do new. Never hurts to ask.


    If you move the spur gear by hand It should slowly turn the tires.


    If turning the drivelines for front and rear work and are smooth,. ( Bad differential ring gear can feel smooth for a bit then not seem right when it hits the broken teeth. )

    Transmission should turn smoothly when fully assembled. turn the input it should turn n feel smooth. Hold onto output to give it load.

    Check the gears in the transmission if underload doesn't seem right.


    A thought I just had. Check the wheel Axel's and make sure they are in the drive cups. Mine pop out often on using the self righting feature. That will make a marble rattling around noise

    Or rocks in the driveline area. Or broken motor. Perhaps cogging from esc to motor wire loose.

    Sent from my Pixel 3 XL using Tapatalk

  4. #4
    RC Champion Acidic01's Avatar
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    Oh btw get Tapatalk app for easy uploading pics n files ect

    Sent from my Pixel 3 XL using Tapatalk

  5. #5
    RC Competitor
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    Nov 2019
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    67
    Double check your transmission bearings. I saw a post in this form about a ball popping out and slinging around inside. I'd also expect scoring on the plastic walls of the transmission if you had something loose in there.

    Sent from my SM-G950U1 using Tapatalk

  6. #6
    RC poster
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    Dec 2019
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    3
    Quote Originally Posted by Acidic01 View Post
    Welcome. Glad you enjoyed the car while it was working.

    The self righting feature is very hard on the cars. It will find the weakest point from motor to wheels. Only use I'd you want to break something unfortunately .

    Can you post a vid of the sound?

    Did you run engine with spur gear or pionion removed, or so that they are not engage by pulling motor away. This checks motor.

    On the center diff. It will be very hard to move the 2 shafts by hand. Much harder than front or rear diffs. You can pop it open and look,. But my guess is it is not inside the center diff with the 4 spider gears. As fluid is 20Mil weight and like putty. I don't think you would get that kind of sound out if it ring gear can break

    If a part did fail give Traxxas a call. Good chance they may send a replacement. Since do new. Never hurts to ask.


    If you move the spur gear by hand It should slowly turn the tires.


    If turning the drivelines for front and rear work and are smooth,. ( Bad differential ring gear can feel smooth for a bit then not seem right when it hits the broken teeth. )

    Transmission should turn smoothly when fully assembled. turn the input it should turn n feel smooth. Hold onto output to give it load.

    Check the gears in the transmission if underload doesn't seem right.


    A thought I just had. Check the wheel Axel's and make sure they are in the drive cups. Mine pop out often on using the self righting feature. That will make a marble rattling around noise

    Or rocks in the driveline area. Or broken motor. Perhaps cogging from esc to motor wire loose.

    Sent from my Pixel 3 XL using Tapatalk
    I'll check the "cogging" and motor soon. I put the shafts on the diff and it indeed turned. I didn't expect that lvl of difficulty on an RX diff...

    I'm fairly certain something is wrong in the transmission... All the grease was bunched into non essential areas ... I pushed it into the race and now the sound is gone and I'm having a hard time recreating any of the issue I had before.. I may have to hook it back up and test...which I don't like...
    Any idea what rating the grease is?

  7. #7
    RC Competitor
    Join Date
    Nov 2019
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    Traxxas sells the right kind of grease. They don't really give a spec for it though. It will always clump up in the empty spaces in the transmission, at high speed it's going to sling itself off the gears like a centrifuge.

    I know it's not what you want to hear, but the transmission can be rebuilt if it goes bad. https://forums.traxxas.com/showthrea...-central-gears

    Sent from my SM-G950U1 using Tapatalk

  8. #8
    RC Qualifier JatoTheRipper's Avatar
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    Full throttle into full reverse, AKA the self righting feature, is hard on parts. Don't use it.

  9. #9
    RC Champion Acidic01's Avatar
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    I use Bel Ray water proof grease as I run at the beach a lot. Sea water and sand is hard on the car. It's a bit stiff at first but works more fluid as time goes on. It also keeps water and sand out of the diffs. I repack all my bearings with it.

    From factory there is only enough grease to coat the gears on the diffs and transmission. I kinda like to pack mine in more, everyone will have their preference.

    Lithium grease from auto parts store can work as well,. Lhs stuff is spendy for the amount. Normal auto part stuff works. Regular auto wheel bearing grease worse as well.

    If you have the transmission apart already, can check all the parts. Look for missing teeth, bearings not rolling smooth ect.

    I'd give the motor a test run not connected to spur gear. I've had one of the ecs wires to motor come out enough to not get a connection but not obvious it was disconnected. I had started tearing drive train apart and then found issue. It makes a odd sound when one of the wires from esc to motor is disconnected, anytime I hear that sound I now know what is wrong. Car stutters as well. With a banging around sound. May be your issue.

    If you don't have one yet a good set of hex tools is well worth it. And the parts explosion diagrams online and paper are nice. Online ones you can click on parts and it pulls up the item to buy off Traxxas website.

    Get a rear chassis brace. https://m.traxxas.com/products/parts/5632

    Depending on your bashing style. Suspension limiting straps. 85mm this will help to stop pulling rod ends out,. Which is a common issue with this truck.

    Sent from my Pixel 3 XL using Tapatalk

  10. #10
    RC poster
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    Dec 2019
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    The same thing happened to me, but it was a bit worse... the spur gear stripped some teeth, and the motor wouldn't spin. The center diff and transmission were good. Turned out the motor blew the rotor magnets. Then while updating the ESC, the app crashed. Traxxas replaced both parts, free of charge. Let us know if the motor is good once you test it.

  11. #11
    RC poster
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    Dec 2019
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    So to close this out -- I picked up Marine Grease (military version of Bel-Ray) we were not able to re-create the issue. We had to pull the spur gear (stripped) and replaced with a metal version. Then packed grease in the transmission. Runs fantastic now. We will not use the self-right feature ever again.

    Thanks for the help guys!

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