Big Rock Arrma big rock

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Fjaimo10

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Arrma RC's
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Arrma big rock 3s 2019
hi just ordered and recieved
ara310947
when come to fit the rear part wont go far enough onto rear diff shaft, had a look and the old part has the lock nut bit alot further down the inside than the new part so that is what stopping it going on
Any ideas
 
I think a picture might help, sounds like you are talking about the slider drive shaft but not sure
 
New part
20200927_105504.jpg

Old part

20200927_105450.jpg
 
Did you buy just a new spur gear or a whole new slipper assembly? It looks like you've replaced more than just the spur gear (ARA310947). It's hard to tell from the pictures, but you may also need to switch to the new shorter input gear in the rear diff: https://www.arrma-rc.com/part/ARA311031 to make it fit.
 
Replaced the whole slipper clutch set up
Sorry was ara311034
 
Then you do need to get the shorter input gear for the rear diff as well. If your diff case isn't fairly new, it will have worn to mesh with your existing input gear and so if you replace the input gear you should also replace the diff case: https://www.arrma-rc.com/part/AR310872
 
Why is that this is supposed to be direct replacement part
 
Direct for new version. If I was doing same thing with my granite v2 I would also need to bring all these same parts up to speed of new version. Jennysrc just buy all new pieces for probably same price
 
Based on the second picture you posted in your original post, your Big Rock is at least 2 years old. You have the octagonal slipper pads. What transmitter do you have?
 
20200927_144646.jpg

Part was listed as direct replacement
Screenshot_20200927-143602_Chrome.jpg

Already fitted a spur gear and slipper pads but the slipper goes loose and slips after a few seconds tighten then does it again so just wanted to replace the lot
 
That is is a discontinued Big Rock, Part Number ARA102723 The correct slipper for your Big Rock is ARA310949.

You can certainly use the new slipper, but not without also changing out the input gear and rear diff cup.
 
Ok
But i will be getting reftund as if u go on modelsport and select my big rock then parts both thoose slippers are listed so they are not correa
 
Last edited:
Sorry, diff case set. If you go that route, you should also replace diff bearings, o-rings and gasket.
 
Do you know which diff case set as obviously not the one already fitted
 
Thanks for advice
But if the new slipper gear wont fit how will replacing parts with whats fitted help
 
You need a shorter input gear to mate with the new slipper assembly. If you put in a new input gear you should also replace the diff case. If you replace the diff case, you should also replace o-rings and the gasket.

You could also try cutting the input gear you have - some on this forum have done that.

You could also try using the old slipper maintenance kit, but don't use the lock nut, but that appears to be out of stock as well: https://www.modelsport.co.uk/index.php?search=1&search_string=AR310882+

You could also try finding a M2.5 x 20mm Cap Head Screw to replace the 25mm screw you have in your new slipper assembly and not use the lock nut. That should work with your existing input gear.
 
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