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  1. #1
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    diff question...HELP!

    I just acquired another Jato via ebay, and i had to rebuild the thing from ground up...man what a sight...made me sad....anyway after 4 hours of cleaning and replacing just about everything but the front end i finally finished.

    Now here's my question...I run my other Jato with an MIP ball diff so the stock one is completely foreign to me. After I built the new diff, when i was done one tire would rotate, but not the other...and so forth on each side..now...when i push the spur when the truck is on the ground, both tires move as the engine would move the truck...is this normal? Is this the "planetary" diff style? Can someone clue me in about how this works?

    Keep in mind that the 2 speed and slipper were purchased seperately, taken out of a brand new Jato at my LHS completely new and untouched.
    I was then given the new diff to put in a day later.

    Any help would be greatly appreciated.

  2. #2
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    Do you have any diff fluid in the diff? If not, or if it's the stock stuff (which is probably half-leaked out anyways), then that sounds about right. Basically, the situation is that the fluid in the diff is not viscous enough to overcome the friction to turn the other wheel, so it turns the next easiest thing, the spur (Assuming your brakes are really loose). If you put in thick diff fluid, like 10k-50k, you should see the other wheel move along with the one you are turning.

    The stock diff in the Jato is a gear diff. Basically, you have two beveled gears perpendicular to another two beveled gears attached to the driveshafts. Diff oil slows the motion of the gears.

  3. #3
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    thanks man...so basically no diff lube is almost is like running a "locked" diff?

  4. #4
    Registered User OneBigMan647's Avatar
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    No, it should be the exact opposite. Since you know your stuff about ball diffs, the stock diff with the stock fluid is like a ball diff in an EXTREMELY loose setting. If you put around 30k in the rear diff you will get the same diff action as a considerably tight ball diff but with a lot less maintenance.

  5. #5
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    if you hold the spur gear and turn one wheel, the other should turn the other way (i know nothing about ball diffs so i dont know if it does the same thing or not) so if you turn one wheel clockwise, the other should turn counter clockwise. if you turn both wheels in the same direction then the spur gear should turn. what you said if you turn one wheel the other wont turn, if the spur gear is turning then the diff is probably working. try putting the brakes on/hold the spur gear and if the other wheel starts turning in the oppisite direction then its working.

  6. #6
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    Quote Originally Posted by jato75
    thanks man...so basically no diff lube is almost is like running a "locked" diff?
    I've talked to alot of Truggy guys and I have tried various silicon thicknesses. The bottom line is that the Jato diff will never perform as a posi-traction or limited slip diff. The only way to get posi-action is to buy a torsen diff. They are very expensive and most of the Truggy guys don't think they are worth it. The Truggy guys deal with changing the fluid in 3 diffs (front/center/rear) in order to get the right action. Basically, changing the
    diff fluid changes how much "diff out" you get. I have a long explanation, but just ask your knowledgeable LHS about "diffing out".

  7. #7
    Registered User OneBigMan647's Avatar
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    If you want to try and lock the diff, team associated sells some 300k diff oil. I know there is 500k diff oil out there but I forgot who sells it.

  8. #8
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    LHS sells a 4 oz. silicone paste. $3.00. I'm using that in a 2.5 diff. Seems to lock up the gears pretty good, but will still allow some slippage. No leakage.
    I tried some 300k.(3/4 oz.$7.00) It's like cold honey! Wanted stiffer yet.
    We'll see how this works out when it gets cold outside. Might strip the gears!lol
    Bus

  9. #9
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    when you guys are saying inbetween 10-50k can you use shock oil or is that something totally different?

  10. #10
    Registered User OneBigMan647's Avatar
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    Diff Oil and Shock oil are both silicone fluids.

    Shock oils range from 10-100wt.

    Diff oils range from 1,000 to 300,000wt. Thus the abbreviation "k". As in 10k for 10,000wt.

  11. #11
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    Quote Originally Posted by WizBus
    LHS sells a 4 oz. silicone paste. $3.00. I'm using that in a 2.5 diff. Seems to lock up the gears pretty good, but will still allow some slippage. No leakage.
    I tried some 300k.(3/4 oz.$7.00) It's like cold honey! Wanted stiffer yet.
    We'll see how this works out when it gets cold outside. Might strip the gears!lol
    What effect are you trying to get by using such heavy silicone? Hope you're only planning on running your Jato in a straight line.

  12. #12
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    What I see, when the jato is turning, is the inside wheel always seems to spin up and balloon at lot. My thoughts are, if I can get both rears to rotate equally, it would make it easier to power slide out of a turn with PL Dirtworks.
    A ball diff will do this by adjusting the tension.
    The Maxx uses different weight "grease" lube to accomplish this too. Or a spool.
    I've experimented with 7 different silicone fluids and pastes. So far, I like the paste the best. It still allows the diff to slip a little when needed.
    It only takes a few minutes to pop a different diff in it. (I have a couple spares). Compressed air and a shop rag cleans them up pretty quick too.

    Yesterday, I put this new single speed I built, in the 2.5 with 18/56 gearing and the ultra stiff diff. It needs a D-box or a way better driver now. It's pretty impressive when you get a good powerslide and rooster tails out of a turn once in a while. She hooks up pretty good on dirt!
    Bus

  13. #13
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    thanks everyone for your comments....i experimented with a couple of different wt. lubes and I just don't like the style of diff it has...the idea that you have to use a different wt. to make your diff tighter kinda stinks...more over the fact that it constantly leaks makes it smell worse. ...i ended up ordering the MIP diff again. That diff rules in my opinion...I've had it in my other Jato for like 5 months now and haven't had to do a thing to it.
    Thanks people.

  14. #14
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    anyone have a link to the MIP ball diff for a jato? Thanks

  15. #15
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    @jato75 when you adjust a ball type diff how do you know if it is to tight or to loose. i'm a noob and have a proball diff so some insight would be very helpful

  16. #16
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    Quote Originally Posted by rb_monster
    anyone have a link to the MIP ball diff for a jato? Thanks
    Here you go: http://www.rcplanet.com/MIP_Jato_Bal..._p/mip1625.htm

    or

    http://www2.towerhobbies.com/cgi-bin...?&I=LXMHB8&P=Z
    If money grew on trees - I'd own Traxxas.

  17. #17
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    Quote Originally Posted by tommrussell
    @jato75 when you adjust a ball type diff how do you know if it is to tight or to loose. i'm a noob and have a proball diff so some insight would be very helpful
    easy....the tighter the screw is in the diff, the more tension you'll feel when you rotate the tires while holding the spur. if you lock it, the tires may not rotate at all. that's how i like to run mine...I like all the power straight to the ground....if it's too loose, you may have slow acceleration, a spooling sound coming from the transmission, or it just act very sluggish.

    hope that helps.

  18. #18
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    yes it did and thank you , it makes more sense to me now

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