Kraton Kraton ring and pinion gears

[cootertwo]

Ah, TP power !!! perhaps a contributing factor? I've got a 4070/2250 ordered. They are supposed to be torque monsters from what I've read.

 

[Pfaulk54271]

Ah, TP power !!! perhaps a contributing factor? I've got a 4070/2250 ordered. They are supposed to be torque monsters from what I've read.

I'd like to say yes but mines only seen the stock motor and a 4092 leopard so far. 1570 TP going in regardless, punch setting is going to 1!

 

[cootertwo]

post #20 shows a TP ???

 

[Pfaulk54271]

post #20 shows a TP ???

That's my brothers rig, mine is now installed as well. Pics coming soon.

 

[Pfaulk54271]

Yess

 

[iLikeRCs]

I wasnt addressing you in my last post. The truck is a gen 3. I'm shimming the same way rich duperbash does. I'm plenty careful with my driving habits. It's totally random, usually front or rear. Awfully easy to point the finger at the user but this is not user error. I noticed my ollllllld once was a nitro kyosho strr evo 2 has larger, beefier diffs than these do.

try using the mugen shims ONLY and between outdrive and between spur/diffcup and outdrive 5x7x25mm shims. As the "Bulletproof new" version in this german video:

hope this helps

 

[Pfaulk54271]

try using the mugen shims ONLY and between outdrive and between spur/diffcup and outdrive 5x7x25mm shims. As the "Bulletproof new" version in this german video:

hope this helps

For the record I am still running that original hot racing diff rebuild. Same bearings and same gears!

????

 

[iLikeRCs]

For the record I am still running that original hot racing diff rebuild. Same bearings and same gears!

????

great!!

 

[Jjmich83]

Hello RC world!
I've got the same issue with my K4s. I'll be honest I am hard on it and I've blown through diffs after switching to the outcast tires. I am ordering all the parts to do a complete rebuild of the front and back diffs. I'm looking for any info on upgraded diff parts, oil to use or just use diff grease. Any help would be much appreciated. I don't know much about gens, I bought the truck in January 2020. I can only assume thats its the newest gen of the 4s. The only upgrades I've done are the tires and a complete bearing replacement.
Thanks
Justin

 

[jondilly1974]

Hello RC world!
I've got the same issue with my K4s. I'll be honest I am hard on it and I've blown through diffs after switching to the outcast tires. I am ordering all the parts to do a complete rebuild of the front and back diffs. I'm looking for any info on upgraded diff parts, oil to use or just use diff grease. Any help would be much appreciated. I don't know much about gens, I bought the truck in January 2020. I can only assume thats its the newest gen of the 4s. The only upgrades I've done are the tires and a complete bearing replacement.
Thanks
Justin

There is only one version of the 4S rigs so far. They were released in 2019 and afaik are untouched so far.

As far as diff oil for inside the diff cup, they come with 5K stock, but that is really too thin. I run 100k up front and 20k rear and like that combo. If you go too thick in the rear like I did (100k rear) then you lose the ability to steer under throttle. You will have to slow down to turn.

As for upgrades, Hot Racing makes all kinds of upgrades, and the one I would recommend first is the aluminum yokes if you are having this many diff issues. Make sure you buy a fresh set of rubber sealed bearings and ensure the diff and pinion are shimmed well. They should be shimmed from the factory, but you will need to verify when you reassemble.

 

[TooTall]

I have a v3 Kraton, that I beat the hell out of regularly, it's stock diffs, never shimmed the diffs, always run 6s, probably has 100 packs thru it easily.

Has Voltage towers, braces. T-bone bumper, other than that pretty much stock, never had a diff problem. Just changed fluid in them a couple week back, things still look good.

If you're burning thru diffs regularly, there has to be some problem with alignment, one post mentioned 5 shims, that seems excessive, sure they aren't too tight?

Or as others said, you may have a crack that is allowing flex or something. I'd grab some v4's from Jenny's or somethign and start fresh with new cases, covers, and diffs.

 

[Jjmich83]

There is only one version of the 4S rigs so far. They were released in 2019 and afaik are untouched so far.

As far as diff oil for inside the diff cup, they come with 5K stock, but that is really too thin. I run 100k up front and 20k rear and like that combo. If you go too thick in the rear like I did (100k rear) then you lose the ability to steer under throttle. You will have to slow down to turn.

As for upgrades, Hot Racing makes all kinds of upgrades, and the one I would recommend first is the aluminum yokes if you are having this many diff issues. Make sure you buy a fresh set of rubber sealed bearings and ensure the diff and pinion are shimmed well. They should be shimmed from the factory, but you will need to verify when you reassemble.

I keep reading that these diffs come with oil but when I pulled my rear one apart the first time, it had diff grease in it. I'm going to give arrma one last chance and rebuild both front and back together replacing the housings and inspecting the mounting blocks for any cracks.

 

[jondilly1974]

I keep reading that these diffs come with oil but when I pulled my rear one apart the first time, it had diff grease in it. I'm going to give arrma one last chance and rebuild both front and back together replacing the housings and inspecting the mounting blocks for any cracks.

If your 4S only had grease inside, that’s wrong. They should have had oil inside, grease outside. You can tell really easy by holding me side and turning the other by hand. You can get a feel for it over time. You can keep an eye on the openness and know when it’s time to refill them.

 

[Jimbobjr]

Where you blowing out the ring and inputs in the stock bulkhead or the hot racing only. Maybe just try the stock one again.

 

[Jjmich83]

I've only had the stock ones. I don't know if I'm ready to drop the money on the hot racing ones yet. The rear diff definitely had black grease on the inside of the diff.

 

[jondilly1974]

I've only had the stock ones. I don't know if I'm ready to drop the money on the hot racing ones yet. The rear diff definitely had black grease on the inside of the diff.

Sounds like dirt maybe got inside as I’ve never seen black grease in any RC. ??‍

 

[olds97_lss]

I haven't had the best luck with the diffs in my outcast... my latest attempt at "making them stronger" was to use the 2 piece arrma diff cups. That was more annoying that it was worth I think.
https://www.arrmaforum.com/threads/issue-with-the-arrma-alloy-diff-cup-seems-too-long.14517/

https://www.arrmaforum.com/threads/...loy-diff-cup-seems-too-long.14517/post-232448

Yeah, I was talking about the ring/pinion, not the internals. I haven't had any of those break on me yet in any of the diffs. This is my 6th diff in 15 months. That's $250 worth of diffs... the first three were when I ran 4S and took about a year! The last 3 have happened in 3-4 months. 2 of which were after installing the arrma alloy cups.

To me, that's excessive. Even in the first year of bashing my savage flux on 4s, I broke 2 or 3 pinions. The ring gears were fine. They were the BP ones. Even my ERBEv1 on 4S never had a diff go out in 3 years! I replaced bearings on them every year, but otherwise, never messed with them.

All I can think is it's partly the depth/size of tooth and partly the material. I bumped the tooth that was rolled over with a dremel on low rpm and it took a decent amount of material away. It should have taken way more effort than that. My other ring gears for pretty much every truck I got are super hard metal.

If there was a ring/pinion that would work, or even a ring gear that worked with arrma's pinion that was made of better stuff, I'd snatch a couple in a heart beat.

 

[slick2500]

Took 5 shims to remove side to side play.

I personally would have went with the 2 piece diff cups instead of the 1 piece, last time I checked the 1 piece units were completely aluminum, the hole where the outdrive goes through gets hogged out rather quickly with those. The 2 piece units have a steel sleeve in there. Steel on steel wears slower than steel on aluminum does.

I am still a firm believer that 99.9% of diff issues are caused by the plastic parts flexing or moving under load.