Just blew brand new diffs in one run...

cobalt172

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I rebuild all 3 diffs in my Kraton and within 10 minutes of a run, there was clicking and then eventually clicking so bad with the car NOT MOVING.

I need someone to tell me what I need to fix this problem. Where/When/How do I shim? Do I need to drop 100 dollars on alum diff housings?
 

jondilly1974

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I rebuild all 3 diffs in my Kraton and within 10 minutes of a run, there was clicking and then eventually clicking so bad with the car NOT MOVING.

I need someone to tell me what I need to fix this problem. Where/When/How do I shim? Do I need to drop 100 dollars on alum diff housings?
Which Kraton? Video of the sound?
 

Kylerc

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You don’t have to post 3 threads in less than an hour to get answers some things take time, be patient and look over the the truck if there’s multiple issues on the same truck I’m sure people will be more than happy to answer multiple questions in the same thread not to mention the wonderful search tool, I can’t count how many times I’ve seen diff issue and pivot ball joint issue threads. Take your time getting frustrated isn’t going to fix anything trust me, and most of the arrmas are some of the easiest (and most fun) to work on in this hobby. Some people can get the plastic diff cups to work just fine, sometimes I think I got the 3s and 4s plastic diffs sorted out and run it turns into a meat grinder. When it comes to the gears inside the diffs the spider gears must all be shimmed with the same size shim. The sun gears are less finicky. Shim the spiders or sun gears and if it gets really notchy the shims are too thick or take the shims out and go to the other gears.
When it comes to ring and pinion i set them till they are a bit tight but meshed properly (pinion not to far in or out) then beat on it till they wear in, clean them up re mesh, load of grease, bash
 

cobalt172

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These are the shims that i see people using in youtube videos (since I tried to search for them here and the search tool is garbage)

Mugen E0206 – Planetary gear?

Tekno TKR1222 13x16x.1mm

Kyosho 96772 13x16x.15mm


Basher 83975 – SKU:9655000127-0
 
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These are the shims that i see people using in youtube videos (since I tried to search for them here and the search tool is garbage)

Mugen E0206 – Planetary gear?

Tekno TKR1222 13x16x.1mm

Kyosho 96772 13x16x.15mm


Basher 83975 – SKU:9655000127-0
The mugen shims are for the arrma sun gears and spiders and the other shims are for the mesh between ring gear and pinion. What exactly broke? The car not moving at all i doubt your 3 diffs are broken... if they are you did something terribly wrong
 

cobalt172

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Which gear is the one that comes in from outside the diff case driven by the drive axel?
 

MrTitanium

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I rebuild all 3 diffs in my Kraton and within 10 minutes of a run, there was clicking and then eventually clicking so bad with the car NOT MOVING.

I need someone to tell me what I need to fix this problem. Where/When/How do I shim? Do I need to drop 100 dollars on alum diff housings?
Use the search engine to find answers on shimming as it’s been covered. Internet isn’t just for watching porn 😉
 

cobalt172

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I just spent 500 dollars on a new ESC (Max6) since the stock one gave out on a 4092 motor, 2 hot racing aluminum diff housings, 2 aluminum diff cups, new ring gears, new input gears, bulkhead covers, 2 new front cvd since one bent, mugen shims and both kyosho shims. Jesus

This hobby is a money pit, but its so fun
 
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I just spent 500 dollars on a new ESC (Max6) since the stock one gave out on a 4092 motor, 2 hot racing aluminum diff housings, 2 aluminum diff cups, new ring gears, new input gears, bulkhead covers, 2 new front cvd since one bent, mugen shims and both kyosho shims. Jesus

This hobby is a money pit, but its so fun
Meshing the diffs are the basics. If your mesh is done correctly and + you have alluminum diff cases your diff should fail under normal bashing use.
 

cobalt172

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Meshing the diffs are the basics. If your mesh is done correctly and + you have alluminum diff cases your diff should fail under normal bashing use.
what? If done correctly they will fail?? Did you mean to say "Shouldn't" fail under normal bashing use?
 

bicketybam

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what? If done correctly they will fail?? Did you mean to say "Shouldn't" fail under normal bashing use?
He meant shouldn't fail.

I've had no issues with the V4 diffs. I never shimmed them internally because they already are. The only thing worth checking is the amount if fluid in them and then the mesh between the input gear and the ring gear. Even that was fine in my Talion. I couldn't fit another shim in there even if I wanted to.
 

cobalt172

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The gear I stripped last time is the input gear, the one that goes into the diff and spins the ring gear. I need to shim that gear because thats the one that keeps getting obliterated
 

chrisexv6

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The gear I stripped last time is the input gear, the one that goes into the diff and spins the ring gear. I need to shim that gear because thats the one that keeps getting obliterated
Make sure the bearings it rides in are OK

Its also possible the diff needs more shimming either towards or away from the input bearing. That would be the shim(s) that go between the ring gear side bearing and the diff housing itself (to move the ring towards the input) or opposite the ring gear side (to move the ring away from the input).
 

cobalt172

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What shim do I place infront of the bearing (inside the diff) and behind the input gear?
I have both Kyosho shims and the Mugen shims
Im also installing 2 hotracing diff housings aluminum to stop any flexing going on with the diff housing
 

chrisexv6

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Surprised at the amount of trouble you seem to be having with your diffs!

Anyway....you don't want to shim the input gear itself, Im pretty sure any shim used there will just eat itself since it would most likely spin with the gear.

What you CAN do is shim behind the inner diff housing bearing. By doing that, it will push the bearing forward (into) the diff housing and when the input gear is installed it will be more forward (into) the diff housing. I don't know the bearing size off-hand, but I think it might be the same as the diff output bearings, which means the same shims used for moving the ring gear can be used for shimming the input bearing.

Precise way of doing it is take a feeler gauge and determine the spacing between your input gear and diff cup, then add shims to get it close(r) with some space left just to make sure it doesn't hit the diff cup.
 

cobalt172

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wait wait wait

OKay so put the shim behind the BEARING that holds the input gear?

Do I use a Mugen or Kyosho shim?
 

jondilly1974

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You put a shim(s) OUTSIDE the bearing. Cram as many as you can and still have a tiny bit of backlash on the input pinion. Just like when you set your motor pinion mesh, you want just a tiny bit of play. The smallest amount you can get before there isn’t any play.
 

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