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  1. #1
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    Monster slash 4x4 diff issues

    I have xo1 diffs and the spider gears in both diffs snapped teeth off the gears. I am running 100k diff fluid in both diffs , proline 2.8 trenchers, and mip x duty axles along with a bunch of other stuff. Why did the xo1 gears shred? I threw in my old spider gears from my stock slash diff and it works fine now.

  2. #2
    RC Turnbuckle Jr. El Sob's Avatar
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    It seems every now and then Traxxas gets a batch of products that has substandard metal used. I had a problem breaking teeth for awhile but I have been lucky lately. The other difference I made was to run 500,000 instead of 100,000.
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  3. #3
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    Quote Originally Posted by El Sob View Post
    It seems every now and then Traxxas gets a batch of products that has substandard metal used. I had a problem breaking teeth for awhile but I have been lucky lately. The other difference I made was to run 500,000 instead of 100,000.

    Performance wise, how does the truck handle differently when it has 500k diff fluid instead of 100k? Also, are there any other diff options out there?

  4. #4
    RC Turnbuckle Jr. El Sob's Avatar
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    Quote Originally Posted by Bigtim29 View Post
    Performance wise, how does the truck handle differently when it has 500k diff fluid instead of 100k? Also, are there any other diff options out there?
    It has better straight line acceleration. It doesn't leak as much.
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  5. #5
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    Quote Originally Posted by El Sob View Post
    It has better straight line acceleration. It doesn't leak as much.

    Thanks. Are there any other diff upgrades you could do to the slash or a whole different diff from another car that would fit?

  6. #6
    RC Turnbuckle Jr. El Sob's Avatar
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    Quote Originally Posted by Bigtim29 View Post
    Thanks. Are there any other diff upgrades you could do to the slash or a whole different diff from another car that would fit?
    As far as I know, the XO-1 differential is the strongest one available.
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  7. #7
    RC Qualifier Rocketzx1's Avatar
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    Quote Originally Posted by El Sob View Post
    As far as I know, the XO-1 differential is the strongest one available.
    What makes the xo-1 diff stronger than the VXL 4x4 diffs? Is it because itís rated for 6s and the VXL ones are rated for 3s? My Rustler 4x4 VXL diffs have been great on 4s for about 3 months now.


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  8. #8
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    Quote Originally Posted by Rocketzx1 View Post
    What makes the xo-1 diff stronger than the VXL 4x4 diffs? Is it because it’s rated for 6s and the VXL ones are rated for 3s? My Rustler 4x4 VXL diffs have been great on 4s for about 3 months now.


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    Check the explode views of both and you will see. If I remember correctly the xo-1 version has two additional pieces, the I-bar and the pin that goes through to resist twisting. I think the xo1 also uses bigger outdrives.

    Ultimately though I think it’s a matter more of 3s running on an off-road and bash vehicle puts a lot more stress on the diff than the same power plant and drivetrain when used on road. So xo1 may run 6s but it doesn’t put the same stress on the diffs as say a 6s e-revo 2.0. The e revo v1 used virtually the same diff as the xo1 and slash 4x4 but used 6mm outdrives, but once it became expected to run 6s, they went to a whole new design for 2.0.
    Last edited by TwoBelugas; 01-27-2020 at 03:41 AM.

  9. #9
    Marshal Double G's Avatar
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    https://traxxas.com/sites/default/fi...-ML-121120.pdf

    The Slash 4x4 uses the same cup as the nitro Revo and T-Maxx. The XO-1's cup is the same as the E-Revo 1.0 and E-Maxx. So you can take the E-Revo cup (3978), i-beam and side plates and install it onto the ring gear of the nitro Revo and have a stronger diff (which is what I did with my Revo). Same is true with the Slash 4x4. You'll see that the spider gears and output shafts are the same. All you need to do is buy the diff gear set to get the i-beam, buy the aformentioned cup, fill with the fluid of choice and install - just be sure to heed the notes about the carrier support (i-beam) and side plates.
    Last edited by Double G; 01-27-2020 at 09:46 AM.
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  10. #10
    RC Qualifier Rocketzx1's Avatar
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    Quote Originally Posted by Double G View Post
    https://traxxas.com/sites/default/fi...-ML-121120.pdf

    The Slash 4x4 uses the same cup as the nitro Revo and T-Maxx. The XO-1's cup is the same as the E-Revo 1.0 and E-Maxx. So you can take the E-Revo cup (3978), i-beam and side plates and install it onto the ring gear of the nitro Revo and have a stronger diff (which is what I did with my Revo). Same is true with the Slash 4x4. You'll see that the spider gears and output shafts are the same. All you need to do is buy the diff gear set to get the i-beam, buy the aformentioned cup, fill with the fluid of choice and install - just be sure to heed the notes about the carrier support (i-beam) and side plates.
    Wow very neat. Iíll have to keep that in mind when I find a slash 4x4 roller I like. You sir, Double-G, are a fountain of information! Thanks man.


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  11. #11
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    I’ve had an e revo 2.0 and the diffs in there are very strong. Would the e revo 2.0 diffs fit in the slash?

  12. #12
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    Quote Originally Posted by Bigtim29 View Post
    I have xo1 diffs and the spider gears in both diffs snapped teeth off the gears. I am running 100k diff fluid in both diffs , proline 2.8 trenchers, and mip x duty axles along with a bunch of other stuff. Why did the xo1 gears shred? I threw in my old spider gears from my stock slash diff and it works fine now.
    I also stripped a few teeth in my diff. But it had some mileage and some wear.
    Slash Ultimate 4x4, MMX-2200kv/Slash 4x4, MMX-2650

  13. #13
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    Is there any way to buy the I-bar separately to the internal gears (5382X and 6882X)?

    The 3978 HD diff cup is affordable, but buying the I-bar is expensive when one already has the gears from the diff being upgraded.

    I imagine 7075 alloy would be strong enough if someone made it, and would lessen rotating mass. Wheel hexes are 6061 alu and theyíre under considerable stress too.

  14. #14
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    No, you got to buy 6882x. I never rebuild a diff with old worn gears. They are now very expensive and when I build them well they last many hours of run time.


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    Slash Ultimate 4x4, MMX-2200kv/Slash 4x4, MMX-2650

  15. #15
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    Thanks mate. Good to know thatís it and stop looking about for it by itself. Good point!

  16. #16
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    I have found the gears wear out over time anyway so unless you are in the diff because of a build error the only part I do not replace is the ring gear. I also have Hot Right AL diff cups so I reuse them of course.
    Diff gears must take a lot of abuse and really they are a weak point, especially after wear and fatigue. Itís just a matter of time. New seals, new gears, and you will be happier because you wonít have to fix the diff again for a while.
    I personally have Castle 1/8 motors and Mamab C ESCs on our trucks and these diffs can take the power of build well.

    However there are some additional upgrades that can be had for added durability. For one the Hot Racing AL diff cup, labeled for a XO-1 and e-max. Also Traxxas makes a set of spiral cut ring and piŮon gears for the front and rear. These hardened gears are spiral cut so more surface area contact so they have improved wear resistance and better transfer of power. Also they seems to be heat treated for extra hardness to improve wear. I love them and although each set is 40$ I think itís worth it.


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  17. #17
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    Iíve been coveting those machined gears for a while. Will definitely have to treat myself sometime in the near future. By all reports they are the bees knees.

  18. #18
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    What I think is happening is under heavy torque the internals move and slip. This is why 6882x and the metal tabs from 3978 is so important. These two kits have parts specifically added to prevent parts moving out of alignment. You can further strengthen the diff with the HR AL diff cup because of its stiffer material holds the gears more precisely thus preventing miss alignment and that causes chipped gears.

    Also as the gears wear from use the gaps increase and then you no longer have those tight tolerances. Combine that with a plastic diff house that has some give and naturally the diff will wear out faster.

    Once I learned what kits are needed and how to properly put it all together almost never have diff failures.

    Itís also important that the rest is the driveline is true and free spinning. Extra resistance because of a bad bearing adds to the wear and tear on parts. I keep on hand extra bearings just so that I can replace them as soon as I see trouble.


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  19. #19
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    These are old cases from my current diffs Iím rebuilding now. Been getting by on the basic ones as long as I could, but that pin bearing on plastic is a glaring weak point.

    This is my OG stampede 4x4 and I try keep everything as in spec and light as possible. Still 2S and a 3650, Tekno shafts, minimal alloy. Have reached the end of the road now though :/



    Gears even chewed into the screws. I was still going to reuse the gears though, figuring Ďahh theyíll wear themselves back togetherí Itís a bit of an obsession of mine trying to resurrect everything until thereís no chance left, see how much I can squeeze from them . I do shim the gears in when I build though.


  20. #20
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    I havenít tried shims, thatís a good idea. That may not work with the AL cups, when I put them together I was a little scared because they where tight! But after a run perfect.

    My sons truck was a Stampede and it never broke and even now some how. He has half the upgrade part I have too!


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  21. #21
    Marshal Double G's Avatar
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    Quote Originally Posted by boosta View Post
    These are old cases from my current diffs Iím rebuilding now. Been getting by on the basic ones as long as I could, but that pin bearing on plastic is a glaring weak point.

    This is my OG stampede 4x4 and I try keep everything as in spec and light as possible. Still 2S and a 3650, Tekno shafts, minimal alloy. Have reached the end of the road now though :/



    Gears even chewed into the screws. I was still going to reuse the gears though, figuring Ďahh theyíll wear themselves back togetherí Itís a bit of an obsession of mine trying to resurrect everything until thereís no chance left, see how much I can squeeze from them . I do shim the gears in when I build though.

    This happened in my nitro Revo. I upgraded to the ERBE diffs and never had the issue again (in ten years!).
    The Super Derecho

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