Typhon Broken rear diff

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lepa32

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Arrma RC's
Hi guys! I bought Arrma Typhon v3 about 2 weeks ago. I've driven it 10 times tops on 4s lipo. Today I heard some clicking noise in rear driveshaft so i disassembled it and gears were completely worn out. There was some sand in diff case, i checked front too and gears were okay but there was some sand too. Is it normal for it to have so much sand in it after about 10 times i've driven it? Because I have Stampede for more than a year and i never had such a problem with it. How is it possible for the rear diff gears to be worn out so quickly? Do you guys think i should contact Arrma? Maybe somebody had this problem?
Sorry for any mistakes, english is not my native language :)
 

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There should not be sand in the diff housing. I've seen some sand trying to find its way into the diff housing with my vehicles, but never inside. The screws that hold the housing to the chassis may have been loose.
 
Yeah, somewhere there's an opening letting sand inside the diff case which is what's wearing the gear set down prematurely. I run in a lot of sand and I've seen a small amount get inside before but nothing like the pictures you took.
The bottom of the diff case is open, so like blindly said check the 4 screws on the bottom of the chassis that hold the case down. If it were me, I would do a complete tear down, clean everything spotless and mock fit everything back together looking for the point of entry of all that sand. Shine a flashlight all around outside the diff towards the bottom of the chassis, looking for light showing inside the diff to find where it's not sealing properly. If the bottom of the diff case is sealed up tight the only other places sand could get inside would be around both bearings and the diff cover that holds the center portion of the sway bars. Something is either loose, cracked or broken, and that what you've got to find to keep the sand out and wearing down the gear set.
 
Thanks for the replies. I'm currently waiting for a response from polish Arrma distributor. I'll definetely try to fit everything back together and check if there's any space left with flashlight. I think that rear gears were worn out because of bad messh. Front had some sand too and gears were okay.
 
Hi lepa,
I have exactly the same problem with my Kraton. I have already replaced both diff cases, but without success. They are always full of sand after a few trips.
In the meantime, have you been able to find out how the sand gets in and what you can do about it?
 
Tekjo make a gasket that goes on the bottom of the diff case. I use grease at the bottom of my case now after seeing a vid from @Primarrma As things flex and depending on the conditions you are driving and jumping it is possible for sand/grit to get in. If you keep an eye on maintenance eg screws like @blindy said. All that being the case, the sand in your pics are on the extreme side in my experience. Did you get the vehicle new?
 
Tekjo make a gasket that goes on the bottom of the diff case. I use grease at the bottom of my case now after seeing a vid from @Primarrma As things flex and depending on the conditions you are driving and jumping it is possible for sand/grit to get in. If you keep an eye on maintenance eg screws like @blindy said. All that being the case, the sand in your pics are on the extreme side in my experience. Did you get the vehicle new?
I'm sure the stock unsealed bearings play a role in this for sure. After 3 months I ate a bearing in my rear diff and when I opened up the gearbox it was full of dirt with shiny metal flakes in it :(
I stuck sealed bearings in and haven't seen much dirt in there during teardowns and I run it in the same place as before.
 
I have had zero issues with the larger bearing inside the diff case, in fact I'm unsure if I have ever replaced them because they were gritty. I think I have simply because after a while I just figured they can't surely just keep going as well as they had so eventually changed them proactively. The outer bearing is another matter entirely.
 
I have had zero issues with the larger bearing inside the diff case, in fact I'm unsure if I have ever replaced them because they were gritty. I think I have simply because after a while I just figured they can't surely just keep going as well as they had so eventually changed them proactively. The outer bearing is another matter entirely.
It was the smaller outer bearing that gave up the ghost, the larger inner bearing was okay. Most internal bearings can last forever, during my last rebuild I reused my year and half old Jim's Bearings inside my gearboxes, both external bearings were starting to get gritty. My stock bearings were all pretty much trashed after a few months of running. Mind you that the dirt where I run is very fine and sandy, I've literally went through a set of motor bearings in one pack :(
 
Had to be loose screws, no way should that much sand get in there.
 
The gaskets work, did you drive through muddy puddles at all? Seal all joins in the gearbox case with grease, you won't get any sand in. Make sure you go around the bearings too.
this guy is pretty boring to listen too, but it might help?
 
I've replaced both diff cases. Used a basket on the bottom part of case and the sand was still getting in through the cover and bearing sides. Then i used silicon to seal cover and bearings and it solved the problem for me. When I open the diffs the silicon stays on plastic parts making a gasket itself so i can easily put it back together. I run in hard sandy conditions so i even had sand coming in to a motor. I also solved it by sealing it with silicon.
 
I've replaced both diff cases. Used a basket on the bottom part of case and the sand was still getting in through the cover and bearing sides. Then i used silicon to seal cover and bearings and it solved the problem for me. When I open the diffs the silicon stays on plastic parts making a gasket itself so i can easily put it back together. I run in hard sandy conditions so i even had sand coming in to a motor. I also solved it by sealing it with silicon.
I'm just going to assume that you used black rtv?
 
No, some silicon that I used in my real car. But i guess black rtv or some other silicon will be ok.
 
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