Rear Diff problems

[GeneralG]

Here is a picture of the rear diff. This was after only 2 tanks of running the buggy that this happened. Looks like the pin broke causing the spyder gear to break or it happened at the same time. Hopefully RedCat will take care of this, find out why it is happening.


Sorry for the quality of picture, was taken with a cell phone. I will get better pictures taken and uploaded here.

 

[Just_Gerald]

Yep, looks exactly like mine did same end even, Did you check your case for a crack?

 

[GeneralG]

Yep, looks exactly like mine did same end even, Did you check your case for a crack?

I don't see any visible cracking on the case itself. I will inspect it today further to find out.

 

[RampageHopUps]

Send me the gears, so I can have them inspected. And then we can figure out what to do.

 

[GeneralG]

Send me the gears, so I can have them inspected. And then we can figure out what to do.

You got it.

 

[RampageHopUps]

Can you get a better picture before you send them. I will take some new ones to a gear engineer and see if he can see any design problems.

 

[GeneralG]

Here are some better pictures of the diff. Looks like it chewed up the main spider gear along with taking a couple of teeth off the 2 other smaller gears, breaking the cross pin and taking a chunk out of the diff hub that the cross pin goes through. The plastic case looks to be ok from what I can tell.





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[Jason]

Just wondering how hard you guys drive as i am a bit of a pussy and don't really like to break things therefor i don't push too hard, do you really give it to the cars or are these faults just that "faults"

 

[PhatDad]

Rob I was looking at the wrong gear when I was talking with you on the phone. I think the HPI gear could be a replacement for the one that broke. I will take a diff apart and compair the two.

 

[RampageHopUps]

The factory is looking for a cause now. We are thinking maybe the pin is breaking, then tearing up the gears??

 

[GeneralG]

The factory is looking for a cause now. We are thinking maybe the pin is breaking, then tearing up the gears??

I would agree with that. What it looks like exactly is the pin broke than tore up the gears. There is still a bit of the pin in the drive cup that is jammed in it still.


I would say that I wasn't pushing the limits of the buggy by any means when the diff grenaded.


Perhaps a larger diameter hardned pin is needed. As the pin is much smaller in diameter than the HPI pin used to secure the spider gear onto the drive cup.


Something else I noticed about the diff. There is only plastic threads where the ring gear bolts/held on to the diff cup with the four hex bolts. This could be a problem after the diff is taken apart a couple of times....

 

[Just_Gerald]

Rob I was looking at the wrong gear when I was talking with you on the phone. I think the HPI gear could be a replacement for the one that broke. I will take a diff apart and compair the two.

No it can't, the HPI gear is amost twice as thick, the smaller spider gears are identical, but the ones we have broke are thinner, the case would need to be made longer.