Kraton HOT RACING DIFF CUP and GPM RACING DIFF CUP

[10pas2]

Well Guys...
Just see the video....and you will see...what a piece of poop this two pieces are....HR and GPM.

What a piece of poop this two brands did....So much slake between diff cup and the input shaft cup... in really unacceptable... Even start to leak diff oil... This has to go viral... Please help me out to spread the word...

 

[Raji]

Is this play from the beginning? or it's starts after you drive it?
Interesting video

 

[10pas2]

Is this play from the beginning? or it's starts after you drive it?
Interesting video

In the beginning was already a little bit of slake, but no leak.... after first run...starts leaking...and i have the 3 diff cups from HR, and all of them with slake and leaking like hell... I already send email to them....waiting...for the reply... let's see...

 

[EndUser]

Hi. Thanks for your post.

I've been running the GPM cups (3 of them) for about six months now and I have not had any issues at all even during this cold Alaskan winter.

I give them a solid recommend.

Since I run 6S most of the time, I added additional internal shims (Mugen specifically) inside the differential which tightened up the whole system. They remain rock solid to this day and without the lateral deflection like you show on your video.

Maybe try and rebuilding using new gears, shims, and O rings?

Good luck,

EndUser

 

[joostin420]

You may have an underlying problem that is causing this. Bent driveshaft, bad bearings, or warped plastic diff housing maybe?

I have not noticed this either. Swapped over all 3 diff cups to hr. From the start though I also swapped over to hr diff housings, and full center mount with top plate. I also swapped over to sealed bearings at the same time and fully shimmed. Nice and tight, and changed to 60k/200k/30k diff oils.

 

[Rtappy1985]

Same here i have 4 arrma rigs all woth hr diff cups and they are amazing. Not a leak on any of the 12 diff cups and while they had a little slack once shimmed propperly they are buttery smooth. I would look for other issues as @joostin420 mentioned.

 

[10pas2]

maybe the shaft was bend...and eat a little bit the diff cup HR....maybe... but is strange...that on the original is quite good!

 

[Raji]

Thanks everyone for sharing

 

[joostin420]

That is definitely strange. Mine definitely did and don’t do that, especially brand-new. Manufacturing tollerences and all, but something doesn’t seem right there for sure. Do you have the orange o-ring installed on the cup side? Which vendor are you getting these from? Have you contacted hr, maybe they would replace after seeing the video of brand-new cup with brand-new output inserted.

 

[10pas2]

That is definitely strange. Mine definitely did and don’t do that, especially brand-new. Manufacturing tollerences and all, but something doesn’t seem right there for sure. Do you have the orange o-ring installed on the cup side? Which vendor are you getting these from? Have you contacted hr, maybe they would replace after seeing the video of brand-new cup with brand-new output inserted.

(And of course i put everything oring,spider,etc)

.I Have already contact HR and they told me :

"I'm sorry to hear about the diff case! These are designed with a bit of play to reduce the opportunity for binding and the play is generally not an issue with the typical viscosities of diff oil used. They can wear over time though and the play could become significant and cause an issue if they're not maintained or replaced when needed.

Best regards,"

Makes some sense....but using 10 packs....already with leaks...?! i didn't notice, when everything was new...if it had so much play...

 

[10pas2]

Looks like...i'm not the only one... having issues with the diff cups...

 

[slick2500]

Looks like...i'm not the only one... having issues with the diff cups...

The only issue I see in this video is that that guy over shimmed his diff. All those marks are from the shims.

 

[10pas2]

The only issue I see in this video is that that guy over shimmed his diff. All those marks are from the shims.

He shimmed the diffs, and then after 8 packs of bat, he notices this....
if he overshimmed...i don't know...

 

[slick2500]

He shimmed the diffs, and then after 8 packs of bat, he notices this....
if he overshimmed...i don't know...

Looks at the back of the gear it's all marked up like that too. I had about 3 months of use on all 3 of my shimmed diffs and none of the gears had those markings on them. There are even marks on the sidewalls of the diffs. As I previously said you can obviously see that those marks are from the shims. He over shimmed his diff and the shims dug into the aluminum. The aluminum diff housing will give out before the steel gears do.