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Anybody ever blow out a inner bearing in diff case?

cordell12

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Got a battery charged up and went out front for a small bash session. Soon as I hit the throttle I heard a grinding sound, I come right back in the house. After some wiggling of this and that I noticed the input hear had a ton of play. Diff cup was fine so I tore into the case. I found the inner bearing all broke apart inside the case. I had just changed diff fluids 2 batteries prior, and last time I attempted to bash I had a small mishap and didn't get to drive. The steering turnbuckle had bent and pulled loose from one of the steering ends. This occurred from doing a double standing backflip, well more like two and a half backflip with damage. I guess now that this also happened with that crash. What does, or what can I do to provide better protection for the bearing. Manual basically shows the input gear rides against the bearing, so the bearing takes all of any incoming force.

20180620_160255.jpg
 

Pauly

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Don't remember if it was the inner or outer I had fail on me. It was quite awhile back on my ET48.3. Took about 8 months of weekly running for failure. Besides replacing them at regular intervals I'm not sure what else can be done.
 

RC_User

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wasn't it @Overkill whom put in much larger bearings there?
 

cordell12

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wasn't it overkill whom put in much larger bearings there?

That I don't know, but knowing him I wouldn't doubt it lol.

Don't remember if it was the inner or outer I had fail on me. It was quite awhile back on my ET48.3. Took about 8 months of weekly running for failure. Besides replacing them at regular intervals I'm not sure what else can be done.

These bearing only had 10 batteries or so through them. I was more worried that I may have put the diff case back together wrong or something. Guess I'll need to keep more of these around.
 

Cmbscx10

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wasn't it overkill whom put in much larger bearings there?

He did. Can't find his post on it but it had to be machined to accept the larger bearing which 99.5% of us don't have the right tools to do so. Shame cause as we know bigger is better on the bearing front.
 

Billl DeLong

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These bearing only had 10 batteries or so through them. I was more worried that I may have put the diff case back together wrong or something. Guess I'll need to keep more of these around.

My bearings typically last for many years, and I often go about 15-20 packs between rebuilds.... I usually wipe the bearings clean and seldom have to remove the rubber seals to flush and re-grease.

By any chance, are you using a shim between the outer bearing and the center out drive?

Without the shim (TKR1226), I can see excessive heat buildup and destroy that bearing in no time :(

42937816151_ddeec59674_o.jpg
 

Slogrits

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My dad just had that happen the front bearing by the input gear disintegrated. This in turn made the center diff fail. He had just built it and only ran about six batteries through it.
 

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cordell12

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My bearings typically last for many years, and I often go about 15-20 packs between rebuilds.... I usually wipe the bearings clean and seldom have to remove the rubber seals to flush and re-grease.

By any chance, are you using a shim between the outer bearing and the center out drive?

Without the shim (TKR1226), I can see excessive heat buildup and destroy that bearing in no time :(

42937816151_ddeec59674_o.jpg

It was the bearing at TKR5405 and there I have no shim. I wonder if adding one may help?
 

Hye

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I have had both bearing get pushed into the diff housing. Yours looks like the bearing just failed.
 

cordell12

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Well I blew out another inner bearing in the rear diff housing. This time I didn't catch it right away and ate up the Ring Gear pretty bad. Maybe I need shims between the input gear and the diff cup? The bearing isn't actually shot out, the seal only popped off. But the Ring Gear is toast for sure. I will be replacing the bearing though.

edit...Input Gear is also toast. This could all be contributed to the previous bearing blow out. I can not be 100% sure though, gears looked fine then

20180701_190707.jpg
 

cordell12

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so I shimmed it out and ran it with slightly bad gears. I chewed up another bearing, and now the gears are 100% shot out. After cleaning the gear box I dropped new bearings in, they just fell right out. I dont think that is normal, so I've also ordered a new gear box. Tekno doesnt break often but when it does it isnt cheap lol.
 

TBuggy

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so I shimmed it out and ran it with slightly bad gears. I chewed up another bearing, and now the gears are 100% shot out. After cleaning the gear box I dropped new bearings in, they just fell right out. I dont think that is normal, so I've also ordered a new gear box. Tekno doesnt break often but when it does it isnt cheap lol.

Send the broken part back to them and you will get a 50% off discount for a replacement.
Cut and pasted from teknorc.com

"All parts covered by our general warranty have a 50% replacement cost if bent, broken or even worn out. The discount cannot exceed 50%, so if you already receive a discount (Team/Military), you will only see a total discount of 50% on returned parts.

See below for parts not covered by this warranty. You MUST send the part(s) back to us – pictures are not sufficient. You MUST include a completed warranty form. We will send you a coupon code via e-mail for 50% off of MSRP for the exact replacement part(s) from our website (shipping not included). Coupons are valid for 14 days from issue date. If you do not purchase a replacement within this time, the coupon offer and warranty are void. This offer is ONLY valid at www.teknorc.com."


I usually buy a new one like you said you are and then return the old one for a spare in the pit box. That way from then on you can always have a good one and one to send back. I also wait to send a whole bunch of parts at once to save on the over all shipping costs.
 

Mirovingian

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so I shimmed it out and ran it with slightly bad gears. I chewed up another bearing, and now the gears are 100% shot out. After cleaning the gear box I dropped new bearings in, they just fell right out. I dont think that is normal, so I've also ordered a new gear box. Tekno doesnt break often but when it does it isnt cheap lol.
So did you get the issue sorted out by any chance?

Been having the same issue and it's even worse cause not even 2 runs down the block with the new diffs, they implode and it's back to the workbench with this thing.

I'm sorely disappointed to say the least, as I had the impression thay Teknos don't have those diff related issues.

I don't even bash the thing such as off ramps or even off road it that much.

If so let me know what the problem was and how you sorted it out.

Thanks.
 

carolinagator

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So did you get the issue sorted out by any chance?

Been having the same issue and it's even worse cause not even 2 runs down the block with the new diffs, they implode and it's back to the workbench with this thing.

I'm sorely disappointed to say the least, as I had the impression thay Teknos don't have those diff related issues.

I don't even bash the thing such as off ramps or even off road it that much.

If so let me know what the problem was and how you sorted it out.

Thanks.
I don't know about yours, but the bearing in the pic above looks pretty dry. Especially for the amount of grease in the diff housing, little rust on the bolt heads and possibly other places too...🤨
 

Mirovingian

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I don't know about yours, but the bearing in the pic above looks pretty dry. Especially for the amount of grease in the diff housing, little rust on the bolt heads and possibly other places too...🤨
Nah it's not that.

It could be a warped pinion gear or something putting pressure on the bearings.

For some reason, in my experience, whenever I run into an issue, that issue just doesn't get resolved no matter how many times I repair it.
 

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