Kraton Shed some light please (help)

[GreatWhiteDope]

Hey guys, got a bit of a long one here, really need some help with my current situation on my K6 EXB v2.
Recently I installed 3 arrma aluminum diff cases. Not sure exactly what’s going on, but they fit horrible on the v2. My guess is maybe they designed them for the plastic diff housings? Anyways, on my front & rear diff, I have had to tinker and change the shimming up several times. On the diffs themselves I can’t fit a shim on the ring side as it just won’t slide into the housing with it. I removed the factory shim (.2mm) from the pinion as it was basically making it rub on the diff case. So no shim was causing to much play, so I decided to add a (.3mm) shim to the outside of the pinion (input cup to outside bearing). Seemed to get rid of the play, and there’s just barely enough clearance to keep the diff and pinion from rubbing. (Pic of clearance with shim)

Now to the center diff, idk what’s going on with it to be honest. I noticed the aluminum diff case was rubbing the hell out of the diff mount and wrecking havoc. Also there was a ton of play for some reason. So I added a shim to the non-ring side to push it further away from the mount. Still a small amount of play, but adding a shim to the ring side made it to tight.
With all these changes the truck drives pretty good, but gets somewhat unpredictable sometimes and feels like maybe my mesh’s aren’t great?
I’m pretty new to the hobby still, and not sure I have a 100% understanding of shims.
Quick overview of the diffs atm,
Front is 80k open, center 500k open, rear 100k open. Truck has the HW 4990 combo in it. I’ve changed my fluids alot trying to find a good setup, anything lighter then 80k seems like it’s just getting cooked(smells that way after a couple runs).

So basically is where I added the shim okay? How can I tell if my diff/pinion mesh is correct? Ideally how much clearance am i looking for between diff/pinion?
Any insight and advise would be appreciated.

 

[Garcbomber]

The input needs to be shimmed on the external side to keep it away from the alloy cup in image 1. Tolerance stack in the bulkhead.

With the center diff, is it possible that you doubled up gaskets? Otherwise the H-carrier could’ve picked up some abrasive debris if it isn’t bent. Rubbing is racing, but also induces a lot of heat.

Grab a caliper and take assembly stack-up measurements before doing any aftermarket or OEM replacement.

 

[Dales396lt4]

My aluminum differentials with spiral cut gears will pull themselves into the aluminum case some but like yours they’ll make clearance doesn’t look pretty but works great as for your center differential I have no experience or advice to add my K6v2 EXB is still stock.

Did you buy just the aluminum Center diff cup and change all the internals over or did you buy the complete differential?

 

[GreatWhiteDope]

The input needs to be shimmed on the external side to keep it away from the alloy cup in image 1. Tolerance stack in the bulkhead.

With the center diff, is it possible that you doubled up gaskets? Otherwise the H-carrier could’ve picked up some abrasive debris if it isn’t bent. Rubbing is racing, but also induces a lot of heat.

Grab a caliper and take assembly stack-up measurements before doing any aftermarket or OEM replacement.

ok ok, so the shim to the outside of the pinion was the right move?
And as for the gaskets I don’t believe so, can double check but I’ve got a good seal and it’s not leaking any oil.
Suppose I’ll order a new center diff mount and see how they look side by side

My aluminum differentials with spiral cut gears will pull themselves into the aluminum case some but like yours they’ll make clearance doesn’t look pretty but works great as for your center differential I have no experience or advice to add my K6v2 EXB is still stock.

Did you buy just the aluminum Center diff cup and change all the internals over or did you buy the complete differential?

Ah that makes sense with the spiral gears, hadn’t thought of that to be the case. So that outside shim makes more sense now.
And yah I just got the diff cases and swapped everything over. Had got them on a crazy sale for 5$ apiece, mainly why i swapped them hah

 

[mikemal]

I tried the center diff and had the same results as you did. The tolerances are too tight for the aluminum diff cup to fit…

 

[Dales396lt4]

Welcome to the forum Mikemal

 

[GreatWhiteDope]

I tried the center diff and had the same results as you did. The tolerances are too tight for the aluminum diff cup to fit…

Yah man I’d say you’re absolutely right. I tried everything I could possibly Think of. Adding shims, changing shims, removing shims. Nothing worked, would still get a poopy mesh, or binding or whatever else. So I took them out, got some new plastic housings and so be it

 

[Dales396lt4]

What about trying to clearance the center diff steel plate that’s rubbing against the aluminum, looks like you could knock 10 Thousand off of that.

 

[GreatWhiteDope]

What about trying to clearance the center diff steel plate that’s rubbing against the aluminum, looks like you could knock 10 Thousand off of that.

What do you mean exactly? Like shimming to move it further away from the diff mount?

 

[Dales396lt4]

The large flat black piece on the center differential is very thick by sanding down the outside. You can reduce the thickness by 10,000s or even 15 and still have recessed screws, which will give you plenty of room to run the center differential you could also as an option, take a little off of the bearing mount/motor mount where the red anodized has already been taken off, if you do that, you have to make it’s flat/ square on chassis, right now it seems off-center a little.

I marked the piece in yellow.

 

[GreatWhiteDope]

The large flat black piece on the center differential is very thick by sanding down the outside. You can reduce the thickness by 10,000s or even 15 and still have recessed screws, which will give you plenty of room to run the center differential you could also as an option, take a little off of the bearing mount/motor mount where the red anodized has already been taken off, if you do that, you have to make it flat right now it seems off-center a little.

Oh ok hadn’t even thought of that. That’s a good idea, I will eventually give them another try as I now own them haha. And that stock center mount is no more! Now have the whole center as M2C. And I’ve got to say it is damned impressive. Flawless fit, everything is so tight and nice and easily accessible.

 

[Dales396lt4]

Very nice looking set up. Does the center differential fit in the M2C mount? I really think the stock motor mount was off-center and not squared to the chassis.

 

[GreatWhiteDope]

Very nice looking set up. Does the center differential fit in the M2C mount? I really think the stock motor mount was off-center and not squared to the chassis.

I changed all the diffs back to the stock cases, then had got the m2c center diff mount a few days after. More than likely I’m going to do some tinkering this weekend. And I’ll rebuild the center diff back into he aluminum case, and do a test fit in the m2c.
It might have been off somehow, which would be strange for sure cus I hadn’t touched it since I did a chassis swap. But then again, that aluminum diff case could have moved it

 

[Dales396lt4]

With the stock stuff there’s enough margin for it to be out of whack but when you upgrade to the aluminum case, the margin is reduced causing interference if the screws are off any at all, it won’t be square and it’ll be closer on one side than the other and this is why the red anodized piece was only hit on one side. This could also be from power and torque twisting things up a little bit.

 

[GreatWhiteDope]

With the stock stuff there’s enough margin for it to be out of whack but when you upgrade to the aluminum case, the margin is reduced causing interference if the screws are off any at all, it won’t be square and it’ll be closer on one side than the other and this is why the red anodized piece was only hit on one side. This could also be from power and torque twisting things up a little bit.

Interesting! Well I guess that part is my bad for assuming an arrma part upgrade should be a good fit.
But I’d potentially put my money on the second part, that Hobbywing combo is crazy power haha

 

[Dales396lt4]

I run the Max6 4990 combo from hobby wing in my infraction & Felony. And the max5 4990 in my limitless. For sure they make plenty of power I love the fact that they’re censored and they don’t overheat.

 

[GreatWhiteDope]

I run the Max6 4990 combo from hobby wing in my infraction & Felony. And the max5 4990 in my limitless. For sure they make plenty of power I love the fact that they’re censored and they don’t overheat.

Oh hellll yah dude, i actually can’t even imagine that system in the infraction or felony. And hell i love the fact it’s Bluetooth. Can make adjustments on the fly so easily. I put a fan on my 4990 just to be on the safe side. Grass romping on a 19t or 20t can get pretty hot

 

[Dales396lt4]

Don’t get me wrong about the heat. I still run dual 40 mm fans on both those cars. If you ever have the need to blow tires off of rims, 8S power will blow tires off the rim instantly. I mostly run it on 6S but I still have to turn the power down to about 70% to make it manageable. I thought about putting that system in my EXBV2 but I really feel it’s a little on the heavy side. But on my EXB v1 I run a max8g2s 4274 2250 KV. With 16t and it rips. It is true. The Bluetooth option really will spoil you and was definitely a selling point for me.

 

[GreatWhiteDope]

Don’t get me wrong about the heat. I still run dual 40 mm fans on both those cars. If you ever have the need to blow tires off of rims, 8S power will blow tires off the rim instantly. I mostly run it on 6S but I still have to turn the power down to about 70% to make it manageable. I thought about putting that system in my EXBV2 but I really feel it’s a little on the heavy side. But on my EXB v1 I run a max8g2s 4274 2250 KV. With 16t and it rips. It is true. The Bluetooth option really will spoil you and was definitely a selling point for me.

I’m so glad you said that about going 8S haha. A week ago or so I was so close to buying a set of 4s batteries to give it a shot. When I first put the system in, it ruined a set of my Gens spammers guess the Lvc was set to low or something and they puffed up a good bit. Ended up just getting a 6s battery.
And yah the v2 is heavy, I’m not exactly sure what mine weighs now but it’s sure as poop a lot more than stock

 

[Dales396lt4]

Plenty of power to be had on 6s