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  1. #1
    RC Enthusiast
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    4X4 feels almost like RWD

    Hi all!

    A friend of mine (really seriously not ME haha) has some weird problem with his Slash 4x4. It feels almost like RWD. Like the 4X4 isnt workin properly. He’s cleaned and re-filled the diffs (30k front and grease on rear), but doesn’t seem to help.

    100k center diff. The slipper made it a tad better but not a whole lot.

    The looser the surface the more of a RWD effect.

    I have same truck with all same setup and parts and I can accelerate at full throttle out of a corner and he has to be really gentle on the throttle. Otherwise he’ll spinn.
    Also makes the rear loose under breaking too.
    Is a lot ”looser” than mine even when you just let go of the throttle.

    Any idea what should we do about it?
    Last edited by Kummeli; 05-13-2019 at 03:08 AM.

  2. #2
    RC Champion RazorRC22's Avatar
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    Turn each wheel by hand, does the diff feel the same as yours does?

    Take off the shocks, do the arms move freely up and down when the shocks are removed?

    Check each shock by itself, can you operate them to full extension/compression or are they hydro-locking?
    youtube.com/c/RazorRCvideos

  3. #3
    RC Racer
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    I have had this happen on a few occasions,
    1.) Stock center driveshaft hub was broken
    2.) Tekno center driveshaft grub screw was loose
    3.) Front axle was broken
    4.) Front wheel and hex were stripped
    5.) The inside of a front hex was torn apart by the pin. Looked fine and spun by hand like normal.
    Last edited by Trojan366; 05-13-2019 at 08:10 AM.
    Slash 4x4
    Rustler VXLs

  4. #4
    Marshal Double G's Avatar
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    Quote Originally Posted by Trojan366 View Post
    I have had this happen on a few occasions,
    1.) Stock center driveshaft hub was broken
    2.) Tekno center driveshaft grub screw was loose
    3.) Front axle was broken
    4.) Front wheel and hex were stripped
    5.) The inside of the hex was torn apart by the pin. Looked fine and spun by hand like normal.
    +1 .
    The Super Derecho

  5. #5
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    Do you or your freind have TSM? If your friend does is it set the same as yours? TSM could also cause control differences. I noticed turning TSM up helped greatly with control of a vehicle.

  6. #6
    RC Champion FnFancy's Avatar
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    I'm all in on front grub screw or shaft. He's probably not getting power to the front axle, hence it feels like a RWD.

    Sent from my SM-N960U using Tapatalk
    Its alright son I'll fix it when you break it

  7. #7
    RC Turnbuckle Jr. Squeegie's Avatar
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    Agreed.
    Check the grub screw on your front drive hub (the part the center drive shaft couples with).

    Good luck!
    Creativity is intelligence having fun. -Einstein

  8. #8
    RC Turnbuckle Jr. El Sob's Avatar
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    I've had a broken hex pin that caused the same problem. A blown differential will also cause the aforementioned problem.
    Member of the 10,000 + posts club! Here to help!

  9. #9
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    Thanks for the replies guys! We’ll check those points out!

    As a note; It does pull with all 4 tires for example if you accelerate from a stand still on gravel.

  10. #10
    RC Champion RazorRC22's Avatar
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    "Thanks for the replies guys! We’ll check those points out!

    As a note; It does pull with all 4 tires for example if you accelerate from a stand still on gravel."

    LOL
    youtube.com/c/RazorRCvideos

  11. #11
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    Quote Originally Posted by RazorRC22 View Post
    "Thanks for the replies guys! We’ll check those points out!

    As a note; It does pull with all 4 tires for example if you accelerate from a stand still on gravel."

    LOL
    What?

  12. #12
    RC Racer
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    When the inside of my front hex was stripped the truck acted like that. The was enough friction to spin the wheel on loose material but under hard acceleration or braking it would slip.
    Slash 4x4
    Rustler VXLs

  13. #13
    RC Champion RazorRC22's Avatar
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    Quote Originally Posted by Kummeli View Post
    What?
    Sorry, I just think it's funny that you report a symptom, and people tell you what your problem is. But there are so many possible causes that it's impossible to just jump straight to an answer.

    IMO, first step is to ask more questions so that you can isolate where the problem is coming from. I don't have the answer, I just have more questions. But eventually you'll get to your answer as you work through it.
    youtube.com/c/RazorRCvideos

  14. #14
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    Quote Originally Posted by RazorRC22 View Post
    Sorry, I just think it's funny that you report a symptom, and people tell you what your problem is. But there are so many possible causes that it's impossible to just jump straight to an answer.

    IMO, first step is to ask more questions so that you can isolate where the problem is coming from. I don't have the answer, I just have more questions. But eventually you'll get to your answer as you work through it.
    Sure I understand all that. I just wanted to make clear that all the wheels do pull since some of the answers felt like they had to do with the front not working at all.

  15. #15
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    UPDATE:

    The hexes are fine. As are the center drive shaft and it’s hubs.

    The diffs feel same as mine (we pulled then apart). However, if you push the axles inwards and turn; my friends rear diff isnt as smooth as mine. You get more of the ”teeth”.

    Also, on front diff there’s more play in the ”hub” that connects the diff to the center driveshaft. And if you turn the hub in some; you can barely turn the diff then. We did put a shimming plate between the hub and the bearing and that took the grinding away.

    So maybe the front diff is really worn?

  16. #16
    RC Turnbuckle Jr. Squeegie's Avatar
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    Time to open it up and inspect.
    Creativity is intelligence having fun. -Einstein

  17. #17
    RC Turnbuckle Jr. El Sob's Avatar
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    I understand that tearing into these trucks can seem a little daunting. Just make sure you do it in a space where you can easily keep track of all of the parts you disassemble. Go slow and enjoy learning about your truck
    Member of the 10,000 + posts club! Here to help!

  18. #18
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    Taking a trick from the on-road world, you might try running lighter fluid in the front than the rear. Running a harder fluid in the rear is essentially like locking the diff, which is pretty much how you might get a drift car to drift.

  19. #19
    RC Turnbuckle Jr. Squeegie's Avatar
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    Haha! At first I thought you were recommending he run lighter fluid in his front diff.
    Not lighter weight silicone diff oil... actual lighter fluid!
    .
    .
    .
    Kaboom!
    Creativity is intelligence having fun. -Einstein

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