Kraton Drive gear wear marks on diff cup ?

[NastyNate]

I'm curious if anyone has seen this?

Is this a big deal or no problem.

This side has always been a problem.

Running (4) shims on the left side of the diff case to take out the slop - seems like alot.

Hot racing case, hot racing diff cup.

Found during rebuilding front case due to broken internal bits.

Pics attached, comments appreciated.

I'm curious if anyone has seen this?

Is this a big deal or no problem.

This side has always been a problem.

Running (4) shims on the left side of the diff case to take out the slop - seems like alot.

Hot racing case, hot racing diff cup.

Found during rebuilding front case due to broken internal bits.

Pics attached, comments appreciated.

First pic did not attach

 

[Andoz81]

I'm curious if anyone has seen this?

Is this a big deal or no problem.

This side has always been a problem.

Running (4) shims on the left side of the diff case to take out the slop - seems like alot.

Hot racing case, hot racing diff cup.

Found during rebuilding front case due to broken internal bits.

Pics attached, comments appreciated.

First pic did not attach

G'day mate, I have seen this before, not in person but in other forums and also on youtube. the issue is the HR diff cup is slightly larger in diameter and is rubbing.
definitely not ideal as it is adding unnecessary friction to your driveline.
The way they fixed them was to put the diff cup into a small metal lathe and machine it down to the correct size.
You would think HR would have there poop together enough to make the part the correct spec. especially with how much they charge for them.

 

[NastyNate]

Thanks for the reply. And welcome to the forum!

I'm going to hack it back together and run it.

More motivation to throw these hot racing diff cups in the trash and put the stock ones back in... or go with arrma cups... I have had zero problems with those.

 

[Mr.Duke]

It’s normal wear. Took a closer look and all seems good ? Bash on

 

[Andoz81]

Thanks for the reply. And welcome to the forum!

I'm going to hack it back together and run it.

More motivation to throw these hot racing diff cups in the trash and put the stock ones back in... or go with arrma cups... I have had zero problems with those.

Yeah I think Ill buy the Genuine Arrma Upgraded diff cups myself if I even need them lol. hopefully not.

 

[Crewchief227]

I had the same issue when I opened the front diff for the first time on my RC8B3E that I got used. It's from the drive cup grub screw slipping on the input pinion. Also that's waaaaay too much grease ?, and the wrong kind. White lithium works in a pinch, but black high pressure grease used in CVDs and whatnot lasts a long time, and a couple of dabs is all you need. ?

 

[NastyNate]

It’s normal wear. Took a closer look and all seems good ? Bash on

Mr. Duke,

Thank you sir - your word is good for me. I will bash on.

I had the same issue when I opened the front diff for the first time on my RC8B3E that I got used. It's from the drive cup grub screw slipping on the input pinion. Also that's waaaaay too much grease ?, and the wrong kind. White lithium works in a pinch, but black high pressure grease used in CVDs and whatnot lasts a long time, and a couple of dabs is all you need. ?

Why is too much lube a bad thing. I'm curious? What is wrong with jizzing into the diff?

 

[Crewchief227]

Mr. Duke,

Thank you sir - your word is good for me. I will bash on.

Why is too much lube a bad thing. I'm curious? What is wrong with jizzing into the diff?

??? ok still trying to catch my breath, even had to show the wife. Anyways, "jizzing" into the diff just causes unnecessary drag in your driveline, thus losing efficiency. Grease isn't there to make things go "faster" it's there to keep wear down to a minimum.?

 

[JtkBrew]

I've read the HR cups are great for the center diff, not so much for the front or rear because of this. I have no personal experience though.

 

[Yas]

I've had the input pinion rub on the stock plastic diff cup and that was from overtightening the diff housing