Big Rock Stripped Input Gear? (Images)

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westryder907

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Arrma RC's
  1. Kraton 4s
So I finally got to breaking down everything and my main input gear looks like this... Also I found a small piece of mangled metal wire inside?
Advice???
20201017_140348.jpg
20201017_134312.jpg
20201017_134323.jpg
20201017_140333.jpg
(See pictures).

What parts should I be replacing here? the rear diff itself feels stern and smooth when turning but obviously this gear would be the culprit correct?
 
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Is the metal from a bearing that died - which then caused the input to be ground down?

Replace the input and diff housing/crown gear as a set and you might need new input bearings as well.

I've ordered this
Housing: https://www.amazon.com/gp/product/B07GR94TM4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Input Gear: https://www.amazon.com/gp/product/B08BJ5S64V/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Bearings: https://www.amazon.com/gp/product/B007KMRYI2/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
Diff fluid (10K): https://www.amazon.com/gp/product/B07P6MK92Z/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
White Lithium Gear Grease: https://www.amazon.com/gp/product/B000HBNV58/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Big tires will destroy them every time. I've smoked 4 .shim tight,good bearings help. I put thicker diff fluid in the rear seems to hook better

I ordered 10K instead of 6K which I believe to be originally used.

Would it be wise to WD40 everything before reassembling or should I use something else to clean the dust that gets in the motor/gear areas? Thanks so much guys/gals!
 
Fyi for future reference you can just order fully assembled diff replacements and outdrives from jennysrc.com, a parts breaker that carries all Arrma stuff pulled from new out of box vehicles. The 3s or 4s diffs/inputs are all the same and will work across both v2 and v3 models. Fill with diff fluid of your choosing then get back out there.

Assembled Diff:
https://jennysrc.com/search?type=product&q=AR310872

Input gear set:
https://jennysrc.com/search?type=product&q=ARA311031

Use coupon code "JRC" at checkout and save 5%, permanent coupon code.
 
I've ordered this
Housing: https://www.amazon.com/gp/product/B07GR94TM4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Input Gear: https://www.amazon.com/gp/product/B08BJ5S64V/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Bearings: https://www.amazon.com/gp/product/B007KMRYI2/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
Diff fluid (10K): https://www.amazon.com/gp/product/B07P6MK92Z/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
White Lithium Gear Grease: https://www.amazon.com/gp/product/B000HBNV58/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1



I ordered 10K instead of 6K which I believe to be originally used.

Would it be wise to WD40 everything before reassembling or should I use something else to clean the dust that gets in the motor/gear areas? Thanks so much guys/gals!
So I finally got to breaking down everything and my main input gear looks like this... Also I found a small piece of mangled metal wire inside?
Advice???View attachment 105011View attachment 105008View attachment 105009View attachment 105010(See pictures).

What parts should I be replacing here? the rear diff itself feels stern and smooth when turning but obviously this gear would be the culprit correct?
I think arrma changed the style of the input shaft because this is what I ordered haven't tried putting it together yet but it's different (shorter)than the one I tore up with the bearing on it.i could dig up the part # if you would like?

16029855762496808648660787775986.jpg


16029856251961321839047530361703.jpg
 
Yes,IVE RAN LOTTA 4S AN SOME OPEN PARKING LOT 6S WITH BIG ROCK AN SENTON.THEY ARE VERY STRONG FOR BEING MOSTLY PLASTIC.REAR DIFFS HAVE BEEN MY MAIN PROBLOM WITH OVERPOWERED 3S LINEUP. BIG TIRES THAT GRIP THAT ARE OVER 5INCHS TALL WOULD SMOKE THEM.HERES LAST TIME i DROVE MY BIG ROCK.SMOKED A POLE AT LEAST 50MPH.haven't got around to rebuilding it.

20200818_202937.jpg

Think I'll start putting it back together. Got all the parts,I've been wrenching on other trucks.
This is what it looks like now..lmao
 

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Yes,IVE RAN LOTTA 4S AN SOME OPEN PARKING LOT 6S WITH BIG ROCK AN SENTON.THEY ARE VERY STRONG FOR BEING MOSTLY PLASTIC.REAR DIFFS HAVE BEEN MY MAIN PROBLOM WITH OVERPOWERED 3S LINEUP. BIG TIRES THAT GRIP THAT ARE OVER 5INCHS TALL WOULD SMOKE THEM.HERES LAST TIME i DROVE MY BIG ROCK.SMOKED A POLE AT LEAST 50MPH.haven't got around to rebuilding it.

Think I'll start putting it back together. Got all the parts,I've been wrenching on other trucks.
This is what it looks like now..lmao

I learned the hard way the significance of a properly set slipper clutch & I agree the plastic used seems pretty durable as long as the slipper clutch is properly set :). and I'm glad the parts are cheap.
 
Fyi for future reference you can just order fully assembled diff replacements and outdrives from jennysrc.com, a parts breaker that carries all Arrma stuff pulled from new out of box vehicles. The 3s or 4s diffs/inputs are all the same and will work across both v2 and v3 models. Fill with diff fluid of your choosing then get back out there.

Assembled Diff:
https://jennysrc.com/search?type=product&q=AR310872

Input gear set:
https://jennysrc.com/search?type=product&q=ARA311031

Use coupon code "JRC" at checkout and save 5%, permanent coupon code.

Do you have any idea how often they restock? I've been watching for pre-assembled rear diffs for my Kraton 4S for weeks.
I tried to replace everything myself and broke the gasket and stripped one of the 4 screws that hold the diff together *sad*
 
Do you have any idea how often they restock? I've been watching for pre-assembled rear diffs for my Kraton 4S for weeks.
I tried to replace everything myself and broke the gasket and stripped one of the 4 screws that hold the diff together *sad*
JRC has lots of the 3s diffs in stock right now. The 3s and 4s diffs are exactly the same gears and diffs are the same in both front and rear diffs. The only difference really is the 4s diffs come with a slightly heavier diff oil in them but is not really even noticeable when driving them imo (6k in 3s vs 10k in 4s). You won't see 4s parts in stock for quite a while because Arrma is getting ready to update the 4s line and isn't shipping the previous model anymore.

Use this search link, it shows all results that will work for your application.

https://jennysrc.com/search?type=product&q=AR310872

20201103_124311.jpg
 
JRC has lots of the 3s diffs in stock right now. The 3s and 4s diffs are exactly the same gears and diffs are the same in both front and rear diffs. The only difference really is the 4s diffs come with a slightly heavier diff oil in them but is not really even noticeable when driving them imo (6k in 3s vs 10k in 4s).

Use this search link, it shows all results that will work for your application.

https://jennysrc.com/search?type=product&q=AR310872

View attachment 107805
The 4S I believe still came with lighter diff fluid than 3S. IIRC the 4S came with 6k and the 3S are all 10k. ??‍♂️✌?
 
The 4S I believe still came with lighter diff fluid than 3S. IIRC the 4S came with 6k and the 3S are all 10k. ??‍♂️✌?
Ooooh you're right and I stand corrected, flip flop those oil weights I said previously, sorry I lied lol ?
 
JRC has lots of the 3s diffs in stock right now. The 3s and 4s diffs are exactly the same gears and diffs are the same in both front and rear diffs. The only difference really is the 4s diffs come with a slightly heavier diff oil in them but is not really even noticeable when driving them imo (6k in 3s vs 10k in 4s). You won't see 4s parts in stock for quite a while because Arrma is getting ready to update the 4s line and isn't shipping the previous model anymore.

Use this search link, it shows all results that will work for your application.

https://jennysrc.com/search?type=product&q=AR310872

Thank you!
I ended up ordering the:

Arrma GRANITE 4x4 3s BLX - DIFFERENTIAL front/rear 37t senton typhon ARA4302V3

That made life so much easier. :D You're all awesome!
 
I think arrma changed the style of the input shaft because this is what I ordered haven't tried putting it together yet but it's different (shorter)than the one I tore up with the bearing on it.i could dig up the part # if you would like?
The new input shaft is shorter to fit the lock nut in the new slipper maintenance kit. It holds the back of the slipper screw. I recently installed them into my Granite and I'm very happy. Holds the slipper screw in place with no loc-tite. Very easy to adjust the slipper without having to re-loc-tite every time.
 
How often do these input gears strip like this? Mine did it today! What can I do to avoid this ever happening again? Turning the punch down, what else?
 
How often do these input gears strip like this? Mine did it today! What can I do to avoid this ever happening again? Turning the punch down, what else?
Hmm... I've taken my Kraton 4s out about 5-6 times just on flat ground and only rolling it / cartwheeling a few of times before I started having rear diff problems again! Hence the signature :]

I haven't even taken it apart because of the weather, so sad.
 
Luckily my local Hobbytown had the case and input gear in stock. $16. Not too bad. I probably could have used the old case. It looked about 95%.

Do people shim these? Is it even possible?
Would the metal yoke really help?
 
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