Differential "skips" on one side

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chrisexv6

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Arrma RC's
  1. Kraton 6s
Rebuilding the rear diff on my Outcast, I noticed an issue that Ive had before: grab the ring gear and turn one of the drive cups. One is smooth, the other feels like it "skips" a tooth or two before actually diffing (turning the other cup).

The last time it happened on our Kraton it was a broken pin under the planetary. On the Outcast, the pin was broken as well...easy fix, right?

Nope! it still skips (albeit less). The gears look intact.....curious if anyone has any ideas what else it might be.

Thanks.

-Chris
 
Rebuilding the rear diff on my Outcast, I noticed an issue that Ive had before: grab the ring gear and turn one of the drive cups. One is smooth, the other feels like it "skips" a tooth or two before actually diffing (turning the other cup).

The last time it happened on our Kraton it was a broken pin under the planetary. On the Outcast, the pin was broken as well...easy fix, right?

Nope! it still skips (albeit less). The gears look intact.....curious if anyone has any ideas what else it might be.

Thanks.

-Chris
Shot bearing(s)? I had this on my hobao truggy, replaced all diff internals then realised it was bearings about £50 later :/

It felt "grindy" to turn and skipped on the one side where one of the ball bearings was misshapen.
 
Shot bearing(s)? I had this on my hobao truggy, replaced all diff internals then realised it was bearings about £50 later :/

It felt "grindy" to turn and skipped on the one side where one of the ball bearings was misshapen.

Hmm...didnt think of that.

This was happening with the diff in my hand, not in the truck so I didnt think it would be a bearing since they werent really "in play" at that point.
 
Pin on the opposite side wasnt sheared?

Nope....thought of that too, took it all apart again and it was good.

The replacement pin fit tightly into the planetary as well, was thinking maybe it got reamed out when running with the broken pin but all looked well.
 
Nope....thought of that too, took it all apart again and it was good.

The replacement pin fit tightly into the planetary as well, was thinking maybe it got reamed out when running with the broken pin but all looked well.


How were the bores in the output cups? Wollered out? Typically if the pin is broken the bore takes a beating, it mushrooms the edges out..

did you try to remove the output cups? If you did, did they slide right out or bind on the way out.? A bind is a dead give away the output cup pin bore is smoked...

This can give a false feeling in the gear bore (feels tight until load is added, then will "click" as the pin moves to the other side of the wollered out bore)
 
How were the bores in the output cups? Wollered out? Typically if the pin is broken the bore takes a beating, it mushrooms the edges out..

did you try to remove the output cups? If you did, did they slide right out or bind on the way out.? A bind is a dead give away the output cup pin bore is smoked...

This can give a false feeling in the gear bore (feels tight until load is added, then will "click" as the pin moves to the other side of the wollered out bore)

That I did NOT check since I do not have spares. Hadn't even thought that could be it, but that makes perfect sense.

Will order some spare drive cups and some drill blanks to use in place of the stock pins.

Somewhat related - ignoring the shimming issues (assuming I can fix them myself), are the EXB diffs heavier duty in regards to the pins, actual gears, etc?
 
That I did NOT check since I do not have spares. Hadn't even thought that could be it, but that makes perfect sense.

Will order some spare drive cups and some drill blanks to use in place of the stock pins.

Somewhat related - ignoring the shimming issues (assuming I can fix them myself), are the EXB diffs heavier duty in regards to the pins, actual gears, etc?


Supposedly Yes.. the pins are larger.. but you need all of the exb stuff...diff cup, output cups, pins, gear set.. ring gear should bolt right onto the exb cup..

edit) hmmm wait, the output cups may have a larger o.d shank.. I cannot confirm this(I don't have the exb) but if they do you are bound to the exb ring and pinion setup... hopefully a exb owner can confirm... @jondilly1974 can probably tell you..
 
Supposedly Yes.. the pins are larger.. but you need all of the exb stuff...diff cup, output cups, pins, gear set.. ring gear should bolt right onto the exb cup..

edit) hmmm wait, the output cups may have a larger o.d shank.. I cannot confirm this(I don't have the exb) but if they do you are bound to the exb ring and pinion setup... hopefully a exb owner can confirm... @jondilly1974 can probably tell you..
Nothing shared between EXB and V4 diffs other than housing.
 
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