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  1. #1
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    Whats weak about the stock diffs?

    Sup peeps

    Im putting together a new truck and the diffs are one of the components id like to beef up. Iv read the diff threads about peeps stripping the spider or ring gears. For some, shimming works for them. Others buy aluminum inner diff cups or aluminum outer housing.

    My question is, what part of the stock revo diffs are the weakest links? (weak spider or ring gears, inner diff cup, outer diff housing, to much gear play?) and which one of these mods have the biggest impact on beefing the stock diffs?

    Losi mod is out of the question so no need to bring it up please.
    E-Revo MMM-2200 6s

  2. #2
    RC Turnbuckle Jr.
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    I went with the hr cups and Robertson racing 8090 ring and pinion and strc case will see how they hold up
    Shimming will help but still get some flex in there depends on how hard you are on it . Some have wasted the spider gears but the hr cup shouldhelp a bit with that

  3. #3
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    Quote Originally Posted by 50togo View Post
    I went with the hr cups and Robertson racing 8090 ring and pinion and strc case will see how they hold up
    Shimming will help but still get some flex in there depends on how hard you are on it . Some have wasted the spider gears but the hr cup shouldhelp a bit with that
    Nice. let us know how that gear set works for you. Im considering replacing the stock gears with an other brand set. Unless they are perfectly strong enough and the weak parts that cause stripping are the inner and outer housing. This is what im tring to find out.
    E-Revo MMM-2200 6s

  4. #4
    RC Turnbuckle Jr.
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    I will keep.you updated!

  5. #5
    RC Turnbuckle Jr. 87 GN's Avatar
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    My question is, what part of the stock revo diffs are the weakest links?

    most time it is the ring gears.. shimming really does help some what....
    Would you go flip my truck back over??

  6. #6
    RC Turnbuckle Jr.
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    I have a good question. Why did robertson racing discontinue the 8090!
    And why doesn't the 8690 work?

  7. #7
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    when you say robertson, do you mean robinson?
    E-Revo MMM-2200 6s

  8. #8
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    the ring gears are usually the breaking points for me, you can go the lst diff mod, this awesome guy by the name of craig.mitch has a thread that has enough information to drown in http://traxxas.com/forums/showthread...6-ERBE-rebuild

  9. #9
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    Yep. Robinson 8090

  10. #10
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    The 1st rule of this thread is to not talk about the awesome LST diff mod.^

    IMO The mesh angle of the ring and pinion gears are not the same. So you get a lot wear on the tips of the pinion teeth and the center of the ring gear teeth.

  11. #11
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    Quote Originally Posted by crashproff View Post
    the ring gears are usually the breaking points for me, you can go the lst diff mod, this awesome guy by the name of craig.mitch has a thread that has enough information to drown in http://traxxas.com/forums/showthread...6-ERBE-rebuild
    Indeed he has alot of good info but its mostly on the lst diff. Im only interested in beefing up the trx diff
    E-Revo MMM-2200 6s

  12. #12
    RC Turnbuckle Jr. MITCH316's Avatar
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    This is my eSlayer build using a beefed up traxxas diff. I am using stock ring and pinion on 2/2s...so far no issues...IDK, it may be of some use to you...post #7 onwards.

    87GN is also building one for 2/3s...post #228 onwards. They may help you.
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  13. #13
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    Quote Originally Posted by craig.mitch316 View Post
    This is my eSlayer build using a beefed up traxxas diff. I am using stock ring and pinion on 2/2s...so far no issues...IDK, it may be of some use to you...post #7 onwards.

    87GN is also building one for 2/3s...post #228 onwards. They may help you.
    Cool thanks for them links. that is similar to what i want to do just not sure if the aluminum cup and housing will be enough.

    87GN. have you tested your diffs with 2x3s? how are they holding up? Your just using the stock gears so would you say the aluminum cup and housing is enough to make the diff bullet proof?
    E-Revo MMM-2200 6s

  14. #14
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    @craig ^^^^The same question goes to you
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  15. #15
    RC Turnbuckle Jr. MITCH316's Avatar
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    I haven't tested this diff case and cup on 2/3s...I was stripping diffs in my eRevo on a regular bases...it because of the way I bash my truck and I only run 2/3s in my eRevo.

    I like to do a lot of freestyle bashing...big jumps, airs, backflips etc. I bought these diffs what you see in my eSlayer build for my eRevo but ended up doing the Losi mod instead...post #8 above is a link to my eRevo build.

    The diffs in my eSlayer are holding up well to 2/2s as my ESC is only rated up to 4s...I think once 87GN's build is complete he will be able to give more insight as to running these diffs with 2/3s power.
    Last edited by craig.mitch316; 12-03-2012 at 05:07 AM.
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  16. #16
    RC Turnbuckle Jr. 87 GN's Avatar
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    ^ That would be correct, just getting started building project URTOAST.....
    Have been doing some powder coating, & time is slowing me down alot.....

    Prob should have gone with the Robinson Ring gears & the alum Carrier & Housing....
    time will tell......
    Would you go flip my truck back over??

  17. #17
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    Well in the 3 years of owning my revo, Iv only ever blew out 1 diff and i run on 2x3s. I also freestyle bash. Maybe not as extreme as craigs bashing but im still ruff on my truck.

    Since iv blown my rear diff and i have the truck all apart, id like to spend money on diff upgrades and not just stock replacements.

    @87GN i keep seeing peeps mentioning Robinson Ring gears but i cant find them on there site. Do you have a link to them?
    E-Revo MMM-2200 6s

  18. #18
    RC Turnbuckle Jr. MITCH316's Avatar
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    Here they are mate...these are what the guys are using

    http://www.ebay.com/itm/ROBINSOS-RAC...item3a7c38a21d

    I am battling to find people who ship these to Australia...I want to put in my eSlayer.
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  19. #19
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    Quote Originally Posted by craig.mitch316 View Post
    Here they are mate...these are what the guys are using

    http://www.ebay.com/itm/ROBINSOS-RAC...item3a7c38a21d

    I am battling to find people who ship these to Australia...I want to put in my eSlayer.
    ooohhhhh ok... ill have to keep these on watch. I already bought a set of GPM hard steel ring gears for my setup. Ill have to see how they do. If not so well then ill see about them RR gears
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  20. #20
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    So my set of GPM ring gears came in today. They feel just a tad thinner then the stock gears. Looks wise i think the stock gear looks stronger but we'll see. Center gear is the stock E-Revos, left gear is stock Slash and right gear is the GPM. The Revos gear is lighter in color then the Slashs. I wonder if that means they are made differently some how,




    I also picked up a set of RDlogic aluminum diff cups. The ibar will need a tiny bit of shaving to fit in the cups. Evrything else seems to fit in alright



    The stock bearings fit on these parts just as they should and they go into the stock diff housing fine but ill be waiting to get some aluminum diff housings before i put this all together. GPM sells the whole diff gear set for these but i couldnt find that kit in stock anywhere so ill just test the ring gear out for now.
    E-Revo MMM-2200 6s

  21. #21
    RC Turnbuckle Jr. MITCH316's Avatar
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    Quote Originally Posted by craig.mitch316 View Post
    Here they are mate...these are what the guys are using

    http://www.ebay.com/itm/ROBINSOS-RAC...item3a7c38a21d

    I am battling to find people who ship these to Australia...I want to put in my eSlayer.
    Quote Originally Posted by Foxprogt View Post
    ooohhhhh ok... ill have to keep these on watch. I already bought a set of GPM hard steel ring gears for my setup. Ill have to see how they do. If not so well then ill see about them RR gears
    The link above I posted is not the correct...the pinion is too long on this model...you need part #8090 not #8690...post #133 has a picture of the #8690 compared with the stock pinion.
    Last edited by craig.mitch316; 12-08-2012 at 05:21 AM.
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  22. #22
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    hmmm i see the teeth are a little on the narrow side on the RR gears. I would think that longer gear shaft would still work specially if your using the stock shafts. Might need some extra washers to shim it up properly. Here was the set i was looking for but ended up getting just the ring gear.
    http://www.gpm-parts.com/shop/produc...roducts_id=211
    E-Revo MMM-2200 6s

  23. #23
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    The new ring gear is probably hardened steel so it should be stronger with that design and weight. Looks like the 8090 gear.
    I know the 8090 gear will not work with the stock pinion. Set it up and give it a turn but the weaker material will wear faster
    And the 8690 pinion being too long would create wear. Too much leverage
    Last edited by 50togo; 12-08-2012 at 10:03 AM.

  24. #24
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    Decided not to use the stock shaft pinion gear with this GPM ring gear. The mesh feels really odd between the two because of the trx more roundish teeth against the gpms more squarish teeth. The stock spider gears would still work but ima buy a kit that includes new spider gears too. It will be a completely new diff. Hope these gears are worth it.
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  25. #25
    RC Turnbuckle Jr. 87 GN's Avatar
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    Impressive... & a good idea not to run the Traxxas gear with the GPM........
    Would you go flip my truck back over??

  26. #26
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    i started this thread a while back...there might be some good info in there for u...

    http://traxxas.com/forums/showthread...-Losi-Diff-Mod

    believe me...i've tried...but there is just no "bullet proof" diff...the only way out is...don't put too much power on the diffs...that's why i kept the ********* 2650kv motor...plenty of power in that motor without ripping the diffs apart...it's that initial low end torque from my 2200kv motor that killed my diff...the new diff that i put in is holding up so far...

  27. #27
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    I am having serious trouble believing that in many years of 3.3/ERBE being on the market, with thousands of optional and hop-up parts, nobody thought to make a decent diff that doesn't break the first time you hit throttle. What gives?

  28. #28
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    Quote Originally Posted by IvVaum View Post
    i started this thread a while back...there might be some good info in there for u...

    http://traxxas.com/forums/showthread...-Losi-Diff-Mod

    believe me...i've tried...but there is just no "bullet proof" diff...the only way out is...don't put too much power on the diffs...that's why i kept the ********* 2650kv motor...plenty of power in that motor without ripping the diffs apart...it's that initial low end torque from my 2200kv motor that killed my diff...the new diff that i put in is holding up so far...

    so how has your diffs been holding up?
    E-Revo MMM-2200 6s

  29. #29
    RC Turnbuckle Jr. MITCH316's Avatar
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    I'll be watching to see how that GPM gear holds up...do they also make pinion gears?
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  30. #30
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    the gpm set is available from hong kong http://www.gpmracing-parts.com/shop/...-90011719.html

    not much info on the pinion length comes with 3 different ones but says fits revo 3.3 that has same gear set as e revo 5379x
    Last edited by 50togo; 12-10-2012 at 06:02 PM.

  31. #31
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    Quote Originally Posted by Foxprogt View Post
    Decided not to use the stock shaft pinion gear with this GPM ring gear. The mesh feels really odd between the two because of the trx more roundish teeth against the gpms more squarish teeth. The stock spider gears would still work but ima buy a kit that includes new spider gears too. It will be a completely new diff. Hope these gears are worth it.
    i mention to 50 about the RR ring gear being squarish and the stock more roundish....best to run them with the right match....do GPM make the pinion gear?
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  32. #32
    RC Turnbuckle Jr. MITCH316's Avatar
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    Quote Originally Posted by 50togo View Post
    the gpm set is available from hong kong http://www.gpmracing-parts.com/shop/...-90011719.html

    not much info on the pinion length comes with 3 different ones but says fits revo 3.3 that has same gear set as e revo 5379x
    Interesting...will have to wait for foxprogt to give some feedback on these gears .
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  33. #33
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    but he doesn't have the pinion for some reason
    i will grab a set for my e maxx it blew a 8090 set over the weekend too

  34. #34
    RC Turnbuckle Jr. MITCH316's Avatar
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    Spell of bad luck you having mate...hopefully all good once the diff is rebuilt .
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  35. #35
    RC Turnbuckle Jr.
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    i tried grinding on the 8690 pinion with a carbide bit-only polished it! didn't even make a dent

  36. #36
    RC Turnbuckle Jr. MITCH316's Avatar
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    Do you think a grinder would do the job...I see the blokes here at work always sharpening their hardened steel drill bits. I thought I may try and grind the sides away .
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  37. #37
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    i didn't want to ruin my bit but don't know it's pretty hard and then if you get it ground the new hole you need to drill will be very close to the other hole

  38. #38
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    I dont have the gpm pinion because i bough the ring gear on its own to try out first. I didnt know the gears teeth would be a different shape then the stock teeth. As posted earlier, there is a whole diff gear set that gpm makes but its out of stock in a lot of places. Im going to buy the pinion and spider gear set as soon as i can and ill post about them.

    I still have a ways to go before i got all the parts i need for my truck so i might be awhile. Hoping to have it running by new years X)
    E-Revo MMM-2200 6s

  39. #39
    RC Turnbuckle Jr. MITCH316's Avatar
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    Quote Originally Posted by 50togo View Post
    i didn't want to ruin my bit but don't know it's pretty hard and then if you get it ground the new hole you need to drill will be very close to the other hole
    I will have to wait for mine to arrive...I was afraid the holes may be to close...some bugger damaged the drill press in the workshop recently...it doesn't look like its drilling straight any more either.
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  40. #40
    RC Turnbuckle Jr. MITCH316's Avatar
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    Quote Originally Posted by Foxprogt View Post
    I dont have the gpm pinion because i bough the ring gear on its own to try out first. I didnt know the gears teeth would be a different shape then the stock teeth. As posted earlier, there is a whole diff gear set that gpm makes but its out of stock in a lot of places. Im going to buy the pinion and spider gear set as soon as i can and ill post about them.

    I still have a ways to go before i got all the parts i need for my truck so i might be awhile. Hoping to have it running by new years X)
    Keep us posted mate .
    Rock n Rolla !

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