# horrible grinding noise coming from my revo 3.3



## matthew77515 (Oct 5, 2009)

ok im new to rc i just bought my first truck(traxxas revo 3.3) yesterday from Joes Hobby Room in LJ (awesome place and very nice people) and i was breaking it in by the book when i got to the 5th tank it started making and horrible grinding noise from the truck and then it would stop for a second or 2 and then it would start agian so i shut it off and when i try to start it now it does it when i try to start the truck any ideas as to what ths could be?:headknock


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## Gary (May 21, 2004)

Wheres the grinding sound coming? The engine or the gear train?


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## matthew77515 (Oct 5, 2009)

it sounds like the gear train?


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## Gary (May 21, 2004)

Check your gear mesh. You should have a little slop.


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## katjim00 (Jan 8, 2009)

Yep check the clutch bell gear mesh. If it is good then maybe the bearings took a poop but highly unlikey. Sounds more like the motor mount adjustment screw came loose. If it did and ate your spur gear I would see if the hobby shop can get you covered.


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## Gary (May 21, 2004)

Since I have never had a Revo, I have no idea if this helps Matt. If it doesnt, check the other vids on the right hand side.


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## matthew77515 (Oct 5, 2009)

Ok i checked the gear mesh i had the correct setting(the paper had the teeth marks on it) and the motor mount screws were tight! but now the sound comes and goes it seems like the higher i rev it is when it starts but when i start to hear it i rev it up more and it goes away and when i dont rev it up the grinding sound kills the engine?


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## Courtney Vaughan (Apr 11, 2007)

does it actually run/drive fine, but is just noisy?

If so, then the EZ start system that is attached to the side of the motor is known to have all kinds of crazy issues with the one-way bearing.


OR, does it seem to jump in/out of gear? If so, then your issue is most likely inside the transmission (the box that is connected to those two gears you just set the gear mesh on)


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## matthew77515 (Oct 5, 2009)

No it doesnt jump in and out of gear and the wheels drive fine, and i took apart the easy start all the gears lined up right and everything seemed to be turning right but wheni put it back together and started i got to run 1 tank of fuel thru it and the noise came back and now it comes and goes? i found a truck on youtube that sounds the same as mine.


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## Courtney Vaughan (Apr 11, 2007)

probably time to venture back over to the hobby shop and seek some in-person assistance......


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## cjtamu (Sep 22, 2004)

Will it go in reverse? Even with the Optidrive, your reverse gear is going to get eaten up. Possible that happened and there are some pieces rattling around making noise. One-way bearing would be the other possibility, but usually not in 5 tanks. I'll try to watch the youtube vid this evening and see if I can tell what it is. When you fire it up, see if you can tell where the noise is coming from (tranny, engine, diffs, etc.). Try the Traxxas forum also, some good guys there.


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## matthew77515 (Oct 5, 2009)

the truck travels fine in reverse and forward and it has no problems shifting. I think the sound is coming more from the rear of the car i thought at first it was coming from the tranny but now that i listen closer it sounds like its coming from the back side of the motor between the motor and muffler?


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## Gary (May 21, 2004)

Front bearing?


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## Courtney Vaughan (Apr 11, 2007)

that has GOT to be that EZ start.........especially if after you took it apart/put it back together it ran fine for a tank. Those one-way bearings are notorious for issues.


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## cjtamu (Sep 22, 2004)

Take it back to the LHS you bought it from and see if they think it's the one-way. If it is, contact Traxxas, their customer support is excellent.


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## kstoracing (Oct 30, 2008)

Ill check my closet to see if I still have my ez start gear. I need to get rid of some of
that junk..


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## Gary (May 21, 2004)

Anybody have some pics of a failed one way bearing? Whats called a "one way bearing", is also called anti reverse on some fishing reels and is used on one our products at work. We call it a clutch though.


Thanks.


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## cjtamu (Sep 22, 2004)

Matt, I sent you a PM on the Traxxas site. Call me tomorrow, I should be home after about 4:30 and I'll see if I can diagnose over the phone.


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## matthew77515 (Oct 5, 2009)

cjtamu i will give you a call tomorrow!


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## Gary (May 21, 2004)

I need closure on this. I hope for the results.


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## matthew77515 (Oct 5, 2009)

i think it is the OWB im im picking up my new one today and i should know something!


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## cjtamu (Sep 22, 2004)

Called you back last night about 6:45'ish, never heard back. LMK if you don't get it solved.


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## matthew77515 (Oct 5, 2009)

ok i fixed! it was the OWB!


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## matthew77515 (Oct 5, 2009)

cjtamu im sorry i was in college but i appreciate you trying to help me out!


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## Gary (May 21, 2004)

Whats a OWB?


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## cjtamu (Sep 22, 2004)

No problem, just wanted to be sure you got it fixed. Biff, OWB = one way bearing.


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