Re-built XO-1 diffs feel notchy. HELP!

[MaXDee]

I'm rebuilding my diffs, except this time besides the i-bar, I'm using those flat little metal parts that go on the outside of the gears before you drop them into the cup.

See the pic below for the flat little metal Parts I'm talking about. I don't know the name of them.

I followed the instructions exactly. I put 30K oil in it. When I tightened down the four cap screws on the ring gear and spun the output, it feels notchy or clicky when it turns. It's not smooth. I've never used these diffs before.

On the gear that goes down into the Cup itself, it calls for a Teflon washer then the blue X Ring. I use green slime on all my X rings and gaskets. What am I doing wrong?

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[RC Dad]

Is it possible that you’ve overtightened the four screws that secure the ring gear onto the diff cup? Did you tighten them little by little in an X pattern? I know those plastic diff cups can be finicky.

Also, if you’ve ever overheated the housing, it could be slightly deformed. The cup itself is cheap enough, if you need to buy a new one.


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[MaXDee]

Is it possible that you’ve overtightened the four screws that secure the ring gear onto the diff cup? Did you tighten them little by little in an X pattern? I know those plastic diff cups can be finicky.

Also, if you’ve ever overheated the housing, it could be slightly deformed. The cup itself is cheap enough, if you need to buy a new one.


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The diff cup , and all the gears are brand new. I did try loosening the four screws in an X pattern as well as tightening them the same way. The screws are snug, but not tight by any means.

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I called Traxxas and talked to one of those guys, and they didn't even know. WHAAAAT?

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[zedorda]

I had a diff turn out like that after new gears being installed and it turned out the casting of the gears was bad. Take it apart and inspect the gears for anything odd. Bet there will be some "misalignments" in their machining.

[grizzly03]

I'm rebuilding my diffs, except this time besides the i-bar, I'm using those flat little metal parts that go on the outside of the gears before you drop them into the cup.

What do you mean? Are you using all the new parts from the #3978 parts including the new diff cup or old cup with those parts you circled?
If you are using all the new parts the I-bar is directional. The rounded end goes towards the cup itself. That would cause issues if backwards.

[MaXDee]

What do you mean? Are you using all the new parts from the #3978 parts including the new diff cup or old cup with those parts you circled?
If you are using all the new parts the I-bar is directional. The rounded end goes towards the cup itself. That would cause issues if backwards.

Yes, all the parts are brand-new including the cup. I just didn't want to confuse people on what I was using as I know there is an upgrade for the slash with just the ibar only.

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[El Sob]

I really advise you to use the complete XO-1 differential. Using only part of it makes it weak. The side plates and I bar make it complete. I used just the side plates and that differential didn't last long.

[MaXDee]

I really advise you to use the complete XO-1 differential. Using only part of it makes it weak. The side plates and I bar make it complete. I used just the side plates and that differential didn't last long.

I am using the complete differential with the I-bar and side plates.

[grizzly03]

Have you tried taking it back apart and test fit the pieces dry (without seals)? Put the output gear in and I-bar with the pin and the two spider gears. Hold down on the I-bar and turn the output shaft. Do they turn good? If they do, next put on the ring gear with the other output gear and see how they turn. If everything turns well, feels good without the seals, reinstall the seals (checking to make sure they are ok) and see how it feels.

[MaXDee]

Have you tried taking it back apart and test fit the pieces dry (without seals)? Put the output gear in and I-bar with the pin and the two spider gears. Hold down on the I-bar and turn the output shaft. Do they turn good? If they do, next put on the ring gear with the other output gear and see how they turn. If everything turns well, feels good without the seals, reinstall the seals (checking to make sure they are ok) and see how it feels.

I haven't tried this, but I am going to do it when I get home from work today. I'll keep you posted.

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[Double G]

Make sure the x-ring seal is seated fully in the recesses within the cup and the ring gear. As previously mentioned, the flat side of the side plates face the gear, the pins face the ring and the rounded edge of the "I"-bar faces down in the cup. I say this because I've made those mistakes. No need to wrench down on the screws, just an x-pattern to tighten until snug.

[MaXDee]

Make sure the x-ring seal is seated fully in the recesses within the cup and the ring gear. As previously mentioned, the flat side of the side plates face the gear, the pins face the ring and the rounded edge of the "I"-bar faces down in the cup. I say this because I've made those mistakes. No need to wrench down on the screws, just an x-pattern to tighten until snug.

Thank you for these reminders. I will make it a point to pay attention to these, especially the x-rings being seated properly.

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[Squeegie]

Good advise there... good luck and keep us posted!

[MaXDee]

Good advise there... good luck and keep us posted!

Will do.

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[jimbo74]

The screws in the carrier are too tight

[Bif24701]

I really advise you to use the complete XO-1 differential. Using only part of it makes it weak. The side plates and I bar make it complete. I used just the side plates and that differential didn't last long.

Yes! The part is 6882x and 3978. If your really want to spend get the Hot Racing XO-1 AL diff cup and Traxxas spiral cut gears for Frnt/Rear.
It’s really important to have those two kits when rebuilding the slash, those little parts help everything line up and lock in place with no movement= longer lasting diffs!
Follow the included instructions well, the I bar must be inserted only one way, the wrong install and it won’t work correctly.

Make sure the x-ring seal is seated fully in the recesses within the cup and the ring gear. As previously mentioned, the flat side of the side plates face the gear, the pins face the ring and the rounded edge of the "I"-bar faces down in the cup. I say this because I've made those mistakes. No need to wrench down on the screws, just an x-pattern to tighten until snug.

Perfectly said!
I have the Hot Racing Aluminum Diff cups so After I have all four screws snug I back one out at a time and add blue lock tight.