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  1. #1
    RC poster
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    About Hoss gear box question

    Why does it automatically jump to the front drive when driving? The rear drive has no power?
    Only 2WD no 4WD

  2. #2
    RC Qualifier GotNoRice's Avatar
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    Probably because of the center differential. It distributes power differently than a vehicle with a slipper clutch. It can help keep the front tires on the ground by shifting power to the front tires in situations where you might otherwise wheelie. Keeping the front tires on the ground obviously makes it easier to steer also. But if you are used to driving a vehicle with a slipper (adjusted tight) then using the center differential can make it seem like it's less punchy.

  3. #3
    RC Turnbuckle Jr.
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    At the hobby store, the owner was much less than impressed with the hoss and the center diff. The pins just rounded off the plastic housing. He showed me. It wasnít pretty.


    Sent from my iPhone using Tapatalk

  4. #4
    RC Turnbuckle Jr. olds97_lss's Avatar
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    Quote Originally Posted by Gripdog7205 View Post
    At the hobby store, the owner was much less than impressed with the hoss and the center diff. The pins just rounded off the plastic housing. He showed me. It wasn’t pretty.


    Sent from my iPhone using Tapatalk
    Surprised they didn't use steel inserts like the ERBEv1 diffs.

    @OP, sounds like your center diff may be low on fluid, or you need to thicken it to suit your driving style. It comes with 500K in it, you could try some 1M to stiffen it up some.
    https://www.youtube.com/c/olds97lss

  5. #5
    RC Qualifier
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    I was surprised to see the plastic cup on the diff but figured they tested it. Thatís too bad if it becomes a weak spot. My 6780 units are very good with all metal construction.

  6. #6
    RC Qualifier GotNoRice's Avatar
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    Quote Originally Posted by TwoBelugas View Post
    I was surprised to see the plastic cup on the diff but figured they tested it. Thatís too bad if it becomes a weak spot. My 6780 units are very good with all metal construction.
    I thought the center differential in the Hoss was the 6780 version with the metal cup?

    https://traxxas.com/products/parts/6780

  7. #7
    RC Turnbuckle Jr. olds97_lss's Avatar
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    Quote Originally Posted by GotNoRice View Post
    I thought the center differential in the Hoss was the 6780 version with the metal cup?

    https://traxxas.com/products/parts/6780
    It lists 9081 as the part with 6781 as optional.

    What's even more odd is that 6781 comes with steel inserts for the x-pins... which makes it even more strange they didn't make the plastic cup to have inserts.
    https://www.youtube.com/c/olds97lss

  8. #8
    RC Racer
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    I have an E-revo 2.0 and I'm curious to why the diff fluid is so thin on the Hoss. With the E-revo the diff fluid is 20 million weight which is obviously very heavy but it handles very well, has lots of power, and still gives leeway for the drive train to give. I understand that the E-revo has stronger parts and more power so there would have to be a factor of scaling the thickness down for the power given, but you would think something like 1 milion weight or something along those lines. From what people are saying (no traction, shredding tires, breaking axles) it seems as if a lot of the problems people are having is from the high power being handled poorly by the center diff.

  9. #9
    RC Turnbuckle Jr. olds97_lss's Avatar
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    If the ERBEv2 wasn't such a pain to get at the center diff, I'd try 1M to see how it did. I had to take it apart twice after refilling the center diff to top it off with 20M as I didn't get enough in it. Ended up using a torch to heat the diff cup so the 20M stuff would soften up enough to get more in it.

    That aside, the amount of free space and size of teeth on the internal gears kind of dictate how thick the fluid needs to be to have any effect.

    My 1/8th arrma center diff has 300K in it and my stampede 4x4 v1 diff with FLM cup uses 500K. If I run any heavier in the outcast, it just wheelies everywhere at the slightest touch of the throttle on 6S. If I run any lighter in my stampede (slash chassis), it diffs out to the front easily with 3S and 1/8th electronics.

    All 3 of which have steel cvd's of some sort.

    It could be that that QC isn't up to scratch and people are getting trucks with diffs that are half filled or something as well.
    https://www.youtube.com/c/olds97lss

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