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Thread: XO-1 Diffs

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    XO-1 Diffs

    I ordered a pair of XO-1 diffs from JennysRC, I havenít taken apart my car yet to install but am curious about the ring gears that came on my diffs. The two diffs I rcvd from Jennyís look to have the same exact ring gears, is there a way to tell if these are two rear diffs or two fronts from the ring gear? I see on the parts diagram, the front vs rear ring gears have different part #ís and I wanted to replace both gears while itís opened up and am just curious which part I need to buy.

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    RC Turnbuckle Jr. olds97_lss's Avatar
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    The difference is the pinion. The front diff has a shaft on the pinion, the rear just has a hole in it for the center shaft/spur/center diff to key into. The diff itself is the same on both ends of the truck/car. At least... I believe that's the case.

    Now I want to count the teeth on the ring gears... lol!

    EDIT:
    Yeah, both sets are 13/37 for the pinion/ring gear.
    Last edited by olds97_lss; 02-19-2021 at 01:27 PM.
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    The Super Derecho

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    Quote Originally Posted by olds97_lss View Post
    The difference is the pinion. The front diff has a shaft on the pinion, the rear just has a hole in it for the center shaft/spur/center diff to key into. The diff itself is the same on both ends of the truck/car. At least... I believe that's the case.

    Now I want to count the teeth on the ring gears... lol!

    EDIT:
    Yeah, both sets are 13/37 for the pinion/ring gear.
    So the ring gears are the same front vs back but the reason the part #ís are different is because the pinions included are different?


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    Quote Originally Posted by Double G View Post
    Thanks for the link to that pdf, I did spend a lot of time going back and forth from the XO-1 pdf to the Slash one, handy to have in one doc!


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    RC Turnbuckle Jr. olds97_lss's Avatar
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    Quote Originally Posted by dordelli View Post
    So the ring gears are the same front vs back but the reason the part #’s are different is because the pinions included are different?


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    Looks that way. Since it seems you can't get the pinion separate. Makes sense, whenever you replace one or the other, both should be replaced so your not prematurely wearing out the other. However, the pinions turn 3 times more than the ring gear, so it would stand to reason that they would wear faster. For the cost though, doesn't make sense not to replace both.
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    RC Champion Panther6834's Avatar
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    Quote Originally Posted by dordelli View Post
    I ordered a pair of XO-1 diffs...The two diffs I rcvd from Jennyís look to have the same exact ring gears, is there a way to tell if these are two rear diffs or two fronts from the ring gear?
    There is NO different between front & rear diffs...they are 100% identical. Take them apart of completely clean every individual part, and then fill them with diff fluid of your choosing. Just remember which you've filled for the 'front' & 'rear', as accidentally "swapping" then could have "interesting" results.


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    Quote Originally Posted by olds97_lss View Post
    Looks that way. Since it seems you can't get the pinion separate. Makes sense, whenever you replace one or the other, both should be replaced so your not prematurely wearing out the other. However, the pinions turn 3 times more than the ring gear, so it would stand to reason that they would wear faster. For the cost though, doesn't make sense not to replace both.
    Yes was just thinking that, gotta buy the ring/pinion set as does not make sense to replace one and not the other. But JennysRC sells the pinions with the driveshaft as a set for just 12 bucks, so will prob buy there. Just wish I wouldíve realized this when I first ordered to save the time and shipping!


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    Quote Originally Posted by dordelli View Post
    Yes was just thinking that, gotta buy the ring/pinion set as does not make sense to replace one and not the other. But JennysRC sells the pinions with the driveshaft as a set for just 12 bucks, so will prob buy there. Just wish I wouldíve realized this when I first ordered to save the time and shipping!


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    Better yet, the Rustler 4x4 listing at JRC has both the correct diff pinions for less then 5 bucks.


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    Whoever is behind JRC, gotta love them for what they do. Obviously, they're turning a profit (if they weren't, they wouldn't still be in business)...but, they're also saving the rear of us (ie. the "end users") a considerable amount of money over purchasing all the individual parts at retail prices. The way I see it, it's a win-win-win-win situation.

    Traxxas wins, because they gain additional RTR sales, this they're still making a profit. Whomever JRC purchases from, they win, because they're also increasing sales & profits (if JRC purchases directly from Traxxas, it's a double-win for them). JRC wins because they've got an almost unlimited supply of customers, and they're also making profit. And, finally, consumers win, because we're not only able to purchase what we wanted/needed, but we're able to save money doing it.

    Obviously, there has to be a 'loser' on all this...I mean, that's always a loser, right? So, who is it? That would be the person looking for the same own you were, except he/she was too slow at the keyboard/mouse, and you beat him/her to the lunch...lol


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    RC Turnbuckle Jr. olds97_lss's Avatar
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    If my ring/pinions give up the ghost now that I'm running 4S, I'll likely give the machined/spiral ones a try. Supposed to be stronger. Cost 3 times more... but if they hold up:

    https://traxxas.com/products/parts/5379R
    https://traxxas.com/products/parts/6879R

    Will have to read up to see if you can run spiral in the rear with straight in the front or not, then at least I'm not spending $90 all at once.
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    Quote Originally Posted by olds97_lss View Post
    If my ring/pinions give up the ghost now that I'm running 4S, I'll likely give the machined/spiral ones a try. Supposed to be stronger. Cost 3 times more... but if they hold up:

    https://traxxas.com/products/parts/5379R
    https://traxxas.com/products/parts/6879R

    Will have to read up to see if you can run spiral in the rear with straight in the front or not, then at least I'm not spending $90 all at once.
    I was thinking/considering this too and on the JRC site, the listing for the slash vxl they are selling the pinion set with the front diff pinion listed as the spiral cut part # and the rear, the not spiral cut, maybe a mistake or I have misinterpreted but if they are pulling these from actual cars, yes u can?

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    Marshal Double G's Avatar
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    They don't come stock with the spiral cut. That question may be best asked of JRC as they are the retailer. I've purchased with them multiple times in the past with very good results, however, if they are advertising it as spiral cut and one gets straight, I would have an issue with it.
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    RC Turnbuckle Jr. El Sob's Avatar
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    Quote Originally Posted by olds97_lss View Post
    If my ring/pinions give up the ghost now that I'm running 4S, I'll likely give the machined/spiral ones a try. Supposed to be stronger. Cost 3 times more... but if they hold up:

    https://traxxas.com/products/parts/5379R
    https://traxxas.com/products/parts/6879R

    Will have to read up to see if you can run spiral in the rear with straight in the front or not, then at least I'm not spending $90 all at once.
    I am 99.9% sure that you can run a spiral cut and a straight cut gear in the same truck.
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    RC Turnbuckle Jr. olds97_lss's Avatar
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    Quote Originally Posted by El Sob View Post
    I am 99.9% sure that you can run a spiral cut and a straight cut gear in the same truck.
    Yeah, they appear to be 13/37 as well... not sure that's as relevant as the OD though.
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    RC Champion grizzly03's Avatar
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    Quote Originally Posted by olds97_lss View Post
    Yeah, they appear to be 13/37 as well... not sure that's as relevant as the OD though.
    Not sure how the OD is going to affect it. Gear ratio is gear ratio. 13/37 (2.846) is still 13/37 (2.846). If they are the same ratio they will turn the same. EX. if the pinion turns say X amount the ring gear will turn Y amount. Going bigger or smaller doesn't change the ratio. The ring gear will stay the same at turning Y amount. Only changing the gear tooth count can change the ratio.

    2.846 ratio number is the ring gear divided by the pinion gear.
    For every one revolution of the pinion gear the ring gear turns 2.846 times.

  18. #18
    RC Turnbuckle Jr. olds97_lss's Avatar
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    Quote Originally Posted by grizzly03 View Post
    Not sure how the OD is going to affect it. Gear ratio is gear ratio. 13/37 (2.846) is still 13/37 (2.846). If they are the same ratio they will turn the same. EX. if the pinion turns say X amount the ring gear will turn Y amount. Going bigger or smaller doesn't change the ratio. The ring gear will stay the same at turning Y amount. Only changing the gear tooth count can change the ratio.

    2.846 ratio number is the ring gear divided by the pinion gear.
    For every one revolution of the pinion gear the ring gear turns 2.846 times.
    I was overthinking it I guess.
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