Diff shim issue/query F & R

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BashingBrian

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Corally RC's
  1. Kronos XTR
  2. Radix
This is just quick guide and to point out that these diffs are a little more complex to fit correctly in their housings..!!

So this is a question for everyone that has taken their diffs apart to service them or are about to, what I'd like to know is do your diffs have the large shims on the outside of the bearing on the right hand side like mine, you can see the large shims between the outdrive cup and the bearing.??

IMG_3012.jpeg


With the new style of flared outdrive cup you can't just slide the shims on after assembly which is quite annoying to be honest, so now to adjust the diff lash correctly you have to build the diff completely, fit it and check for play, then disassemble the diff add or remove the shims as needed then fit back in the car 🤔

Here you can see all the parts from my front diff all laid out, top left are the two large shims.

IMG_3016.jpeg



In this exploded diagram there are no large shims pictured, but so far everyone of mine has had these shims..!!
The purpose of these missing shims is to remove any lateral play in the diff whilst it's inside the housing, and also to push the ring gear into the pinion so as to remove any play in the gear mesh.
It seems a bit weird to me that in all the Corally manuals I've seen so far these large shims are just not shown, as every other car I own regardless of brand they have these shims fitted and shown in the manuals..🤔

This particular manual below is a Radix 6s.
Screenshot 2022-02-22 at 17.43.19.png



My overall opinion of these diffs is they have a very good fit and finish, they're also beefier than stock Arrma diffs in my opinion.
I'd suggest taking your time to build them as they feel very nice when built correctly, shim the outside well so as to remove any play you may have in the diff housing.

Once I rebuilt mine they felt very smooth with no binding whatsoever, I then used the large shims that were fitted from the factory and my diffs are nice and tight in the housings with no lateral play..!!

Good luck 👍🏼
 
Mine were exactly the same.
I double checked their shim job by putting one shim on each side of the cup but that was not good mesh so I returned it to how the factory has it.

I agree that these are very nice diffs!
 
This is just quick guide and to point out that these diffs are a little more complex to fit correctly in their housings..!!

So this is a question for everyone that has taken their diffs apart to service them or are about to, what I'd like to know is do your diffs have the large shims on the outside of the bearing on the right hand side like mine, you can see the large shims between the outdrive cup and the bearing.??

View attachment 1247

With the new style of flared outdrive cup you can't just slide the shims on after assembly which is quite annoying to be honest, so now to adjust the diff lash correctly you have to build the diff completely, fit it and check for play, then disassemble the diff add or remove the shims as needed then fit back in the car 🤔

Here you can see all the parts from my front diff all laid out, top left are the two large shims.

View attachment 1246


In this exploded diagram there are no large shims pictured, but so far everyone of mine has had these shims..!!
The purpose of these missing shims is to remove any lateral play in the diff whilst it's inside the housing, and also to push the ring gear into the pinion so as to remove any play in the gear mesh.
It seems a bit weird to me that in all the Corally manuals I've seen so far these large shims are just not shown, as every other car I own regardless of brand they have these shims fitted and shown in the manuals..🤔

This particular manual below is a Radix 6s.
View attachment 1245


My overall opinion of these diffs is they have a very good fit and finish, they're also beefier than stock Arrma diffs in my opinion.
I'd suggest taking your time to build them as they feel very nice when built correctly, shim the outside well so as to remove any play you may have in the diff housing.

Once I rebuilt mine they felt very smooth with no binding whatsoever, I then used the large shims that were fitted from the factory and my diffs are nice and tight in the housings with no lateral play..!!

Good luck 👍🏼
Can't remember if I had my xtr diffs out yet or not, but do know the outdrives on my Xray xb8 are flaired like that too. I believe the Xray as well as Tekno rarely need any shimming due to their high manufacturing standards.
 
Good write up. I did pull them when I first got the Sketer to check em out. I did notice that you can’t get the shims off without pulling the cups. I thought about cutting some when it comes time to rebuild just to get it perfect before pulling it back apart to put uncut permanent shims on the diff. Guess we’ll burn that bridge when we get there.
 
Very Good write up and thanks for the post this is great info for newbies and vets alike!
 
And they provide you with some spare shimms!
They are hidden in the front steering hubs :sneaky:
That's just brilliant 🤪🤣


On second thoughts though, are they in there to take out some slop in the drive stub axle ???🤔
Note to self.. Buy spare shims 👍🏼
 
I reinstalled the shims in the front carriers when I put the HD on..didn't even think of checking for freeplay at the axles🙄🤣 all went together smoothly except the stupid pivot ball cap that cross threaded ITSELF!! Boy, those caps are so stupid! It wasn't MY fault!🤪😬🤣
 
@KnowAir ....
Not sure if this would fit the Corally pillow ball caps, but if it does it's a great tool, I have one and it is awesome when fitting the Arrma ones 👍🏼😉
https://m2cracing.net/notorious-v5-exb/548-m2c-3327-arrma-pillar-ball-wrench-.html
Thanks for the link👍 eventually I'm going to buy some M2C goodies, I'll add that to my list.
But yeah, I cross threaded one of my xtr caps. Tried to reinstall but no bueno, I just sent it in crooked🤪 gonna run it as is for now. I have spares for the Arrmas, but not TC..for all I know they may be the same. It went in so hard, I know it'll be destroyed taking it back out soo😬🙄
 
This is just quick guide and to point out that these diffs are a little more complex to fit correctly in their housings..!!

So this is a question for everyone that has taken their diffs apart to service them or are about to, what I'd like to know is do your diffs have the large shims on the outside of the bearing on the right hand side like mine, you can see the large shims between the outdrive cup and the bearing.??

View attachment 1247

With the new style of flared outdrive cup you can't just slide the shims on after assembly which is quite annoying to be honest, so now to adjust the diff lash correctly you have to build the diff completely, fit it and check for play, then disassemble the diff add or remove the shims as needed then fit back in the car 🤔

Here you can see all the parts from my front diff all laid out, top left are the two large shims.

View attachment 1246


In this exploded diagram there are no large shims pictured, but so far everyone of mine has had these shims..!!
The purpose of these missing shims is to remove any lateral play in the diff whilst it's inside the housing, and also to push the ring gear into the pinion so as to remove any play in the gear mesh.
It seems a bit weird to me that in all the Corally manuals I've seen so far these large shims are just not shown, as every other car I own regardless of brand they have these shims fitted and shown in the manuals..🤔

This particular manual below is a Radix 6s.
View attachment 1245


My overall opinion of these diffs is they have a very good fit and finish, they're also beefier than stock Arrma diffs in my opinion.
I'd suggest taking your time to build them as they feel very nice when built correctly, shim the outside well so as to remove any play you may have in the diff housing.

Once I rebuilt mine they felt very smooth with no binding whatsoever, I then used the large shims that were fitted from the factory and my diffs are nice and tight in the housings with no lateral play..!!

Good luck 👍🏼
Mine were the same. I keep bending those shims. They are annoying to install. I just shimmed the diff pinion gear instead. I'm hopping this fixes the issue I'm having with the rear diff slipping.
 
Update on the stripped hub carrier pivot ball cap I duffed a while back..I decided to try and tighten the cap a tad since the cross thread capped pivot ball had a bit of play in it..no bueno. Stripped the hex, so I got the damaged cap out, put a spare Arrma cap in there, seems to have gone in straight since it didn't fight me all the way like the cross threaded TC cap had previously..so I was able to save the TC upgraded carrier after all🤘🍻.
As to the diff shimming, still haven't touched the front or rear yet. Everything there seems happy so not in any hurry to tear em down but I do have an issue with my rear outdrives showing quite a bit of wear so it won't be long till I have to dive in unfortunately. Guess I'll have to order up some of those fancy bronze colored ones..although sketer owners don't seem to be having much luck with those either..
I think my biggest personal gripe with the xtr is drivetrain wear.. I don't see nearly as much on my Arrma's given the same(or close to) usage.. I only own EXB models from Armma so maybe that may have something to do with it but the XTR is TC's premium model also..
To put it into further perspective, I own Redcat, Traxxas, Thunder Tiger, Arrma, TC, Tekno and X ray rc's currently..the Redcat kaiju is the only other besides the XTR that I see what I consider rapid wear in the drivetrain parts. Of course the Kaiju was a cheapish rig to start so no surprises there.. I expected better from TC though.
 
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