whats this sound? (video!) diff??

northeastflyer

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just cleaned the rear and front diffs after noticing this weird sound. I think it was impacting speed in the field as the pack.


edit VIDEO actually has SOUND now!

I do want to get back in and replace the bearings on those diffs as they look like the sand and dirt has done a number on them but not convinced the noise is from them.

could it be the motor? the center diff? slipper clutch? (nvm i don't have one)

It was a hot day yesterday and I basically ran pack 1 pack 2 and pack 3 back to back under the sun.
 
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bicketybam

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I can tell you it isn't the slipper clutch because it doesn't have one 😅

It sounds like a chewed up diff/input gear to me.
 

northeastflyer

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I can tell you it isn't the slipper clutch because it doesn't have one 😅

It sounds like a chewed up diff/input gear to me.
thanks for the reply. I didnt drain the diffs but I had a look and nothing seemed broken. Althought I guess without draining it and taking it fully apart I can't really tell if anything is broken, correct?

I guess next up is to explore the center diff housing and look there.
 

bicketybam

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thanks for the reply. I didnt drain the diffs but I had a look and nothing seemed broken. Althought I guess without draining it and taking it fully apart I can't really tell if anything is broken, correct?

I guess next up is to explore the center diff housing and look there.
Start by taking a good look at the teeth on the outside (ring gear). Also check the input gears. If you want to check the inside gears, start my turning the rear wheels by hand in opposite directions. Turn them back and forth. If I e of the inside gears is broken you will most likely feel it. Do that with the front and the rear.
 

northeastflyer

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Start by taking a good look at the teeth on the outside (ring gear). Also check the input gears. If you want to check the inside gears, start my turning the rear wheels by hand in opposite directions. Turn them back and forth. If I e of the inside gears is broken you will most likely feel it. Do that with the front and the rear.
I don't think there is anything broken in the rear and front based on that technique to test. Feels pretty good everything is spinning well w no noise when doing wheels in opposite directions.

Center diff here I come

btw - What am I looking for with respect to the input gears in the event theyre messed up?

Must be the center then.. Go
 

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If this is from your diff that you showed the other day, it's the input gear in the rear diff slipping. Also the spur gear shows some flat spots which is exactly where this slipping occurs. Leave the middle diff alone, it can't cause what you are experiencing.

From the pictures, you didn't have the housing mounted correctly or it loosened up on you, evidence of dirt around the upper screws. That pretty must destroyed the gears inside. Make sure it's tight.

https://www.arrma-rc.com/part/AR310498

If possible, get an entire diff from Jenny's and you can swap parts or have a replacement for issues like this.
 

northeastflyer

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If this is from your diff that you showed the other day, it's the input gear in the rear diff slipping. Also the spur gear shows some flat spots which is exactly where this slipping occurs. Leave the middle diff alone, it can't cause what you are experiencing.

From the pictures, you didn't have the housing mounted correctly or it loosened up on you, evidence of dirt around the upper screws. That pretty must destroyed the gears inside. Make sure it's tight.

https://www.arrma-rc.com/part/AR310498

If possible, get an entire diff from Jenny's and you can swap parts or have a replacement for issues like this.
thanks very much. figured it was in the rear but couldnt help get in there
:)

thanks again
 

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jkflow

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Might as well do some maintenance! (y)
Issue is in the rear one though. You might be able to shim yourself back into compliance but that sounds like is too far gone.
 

northeastflyer

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Might as well do some maintenance! (y)
Issue is in the rear one though. You might be able to shim yourself back into compliance but that sounds like is too far gone.
how does this look? wondering if this would also need to be replaced in addition to the gear. the teeth look consistent where as on the gear not so much in places.

don't mind the grease i added after that initial cleaning. lol
 

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bicketybam

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how does this look? wondering if this would also need to be replaced in addition to the gear. the teeth look consistent where as on the gear not so much in places.

don't mind the grease i added after that initial cleaning. lol
Hard to tell, but I don't think it looks good. Some of those teeth are really pointy. That usually a sign that they are worn.
 

jkflow

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I'm with @bicketybam, that input gear is toast. You will see what we mean when you hold it next to a new one.
If that screw is rounded, GET SOME BETTER TOOLS! :)
As bickety stated use a dremel and do what must be done.

As before a mini torch would have worked just fine on that one, 30s and it would almost fall out by itself..almost..
 

northeastflyer

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I'm with @bicketybam, that input gear is toast. You will see what we mean when you hold it next to a new one.
If that screw is rounded, GET SOME BETTER TOOLS! :)
As bickety stated use a dremel and do what must be done.

As before a mini torch would have worked just fine on that one, 30s and it would almost fall out by itself..almost..
roger that. i did try heat. better tools en route

do you have a recommended flat head that would be strong enough but also to fit in there when I do the dremel work?
 

bicketybam

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roger that. i did try heat. better tools en route

do you have a recommended flat head that would be strong enough but also to fit in there when I do the dremel work?
I use any one of my countless flatheads that I have laying around. You don't need anything special.
 

jkflow

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You ,might be able to just hammer in a torx head, can't hurt anything. The input gear is gone i.e. bending the shaft makes no difference and the bearings should be replaced as well, still support it somehow with a wood shim or something.
 
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northeastflyer

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Have a new rear diff kit coming. I’ll replace the spur and the input gear, and change the bearings.
 

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