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Discussion Starter #1
I can’t believe this band new Traxxas Bandit is slipping gears.

Please someone tell me it isn’t so.

I bough this RC buggy not to race or beat on but to mount it with a video camera.
I have a TC3 with a video camera, but the ground clearance is way to low for exploring. I figured if I spend $100+ for a RC buggy type unit I could mount it with a high-resolution camera and get some cool Waikiki beach shots.

From what I had heard, the Bandit would have made a good candidate for this project.
But now I really feel like I bought a peace of junk.

So I’m asking everyone to download the short videos, view and listen to that striping sound and give me your advice on what I should do with the buggy (All advice: positive or negative is welcome).

Click here to view video MPG2 4mb
http://photos.imageevent.com/maximundo/electronics/traxxas_gear_slip_mpg2.mpg

Click here to view video MPG1 476kb
http://photos.imageevent.com/maximundo/electronics/traxxas_gear_slip_mpg1.mpg
 

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I only downloaded the short vid, but from previous (and current) experiance with traxxas trannys, I would say the slipper clutch is slipping. download the PDF file link below and look for the spur gear at the bottom. there is a locknut that compresses a spring (part #s 1747 and 1994 on the pic) that adjusts how much the slipper slips. Because your going to be carrying a camera on the bandit, I doubt you will be doing any jumping or bashing (at least with the camera on) so go ahead and torque down the spring untill it wont go anymore. If that does not work, post again. all the stampede guys should show up because the pede and bandit use the same tranny (yes, thats you Tom)
http://www.traxxas.com/products/electric/bandit/blueprints/Bandit tranny assy.pdf
 

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that's a heck of a sound for it to be the slipper slipping. even a loose slipper shouldn't slip like that on a freewheel. By the video I would also say that the spur is rotating at a constant speed while the wheels are cogging badly.

Depending on the age of the bandit it may have two separate screws that tighten the yoke onto the output shafts from the tranny. If its the "old style" they could have come loose and be slipping on that squared edges of the shafts. If they are the new style there will only be one screw per side and it will go all the way through the output shaft eliminating the ability to slip.

If that doesn't appear to be the case it could be a stripped idler gear inside the tranny case. If that's the case traxxas sells a replacement aluminum one which is around $10.00 and should fix the problem.

Besides the video, any other input as to wear exactly that sound is coming from, is the spur spinning or do you feel it's slipping, and do you have new or old style output shafts?

If you think it may be inside the tranny there is a great pictoral at Misbehavin RC Transmission Teardown. He also has a tutorial on Slipper Clutch adjustment. Let us know what you come up with.

Good luck!
 

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That is an odd one, for sure. it dos not sound like yoru idler which is good. I would definitely try to lock down the slipper and see if it goes away as a first step. When you are doing that the wheels are in the air?

More info please:

-age of buggy- looks brand new
-age of motor- the Stinger can be a snarky little motor.
-how well is the spur gear adjusted?- you MIGHT get a noise like that if it is too tight (or badly worn with sand and stuff in the teeth) but that doesn't explain the cogging. it is hard to tell if the spur is really keeping up speed or whether everything is dragging.

Trouble shooting a Traxxas truck isn't that hard as there are a limited number of things that could go wrong but lets start with those.
 

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The 4 meg didn't work, but the smaller did. I watched it several times and the nut on the slipper seems to move the same as the drive shafts. so I would say you have a slipper real loose & you should tighten it. The rest of the noise sounds an awful lot like gear mesh, the pinion is meshing hard against the spur and needs to be backed off.
 

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Just FYI, the motor shaft gear is called "Pinion"

Also, when your adjusting the pinion/spur gap make sure you check the gap around the whole circumferene of the spur. It's very common for a spur to be slightly out of round. When you set your gap set it at the tightest spot on the spur. Make sure you can slightly wiggle the spur while in contact with the pinion. This way you never have a "tight" spot during the revolution of the spur.

Good luck
 

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Discussion Starter #9
"It's very common for a spur to be slightly out of round"

Sounds like a quality control issue.
Mine seems ok but how would they become out of round?
Unless you mean worn arias. I can imagine a user striping a spot on the gear and leaving an aria where the teeth are ground down. If that’s what you mean.
 

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no no.. It's definitely a quality control issue.

I've seen brand new Traxxas "white" spurs that have a tight spot and a loose spot in the rotation of the spur. That being said the spur is "out of round". I've also seen the same thing with the HPI carbon spurs for traxxas (highly recommended as a tough spur compared to stock) as well as the Kimborough spurs.

Again, not all of them are like this but when you change spurs you want to check. I've been down this road multiple times as my son and I have 2 electric rustlers and a stampede.

If you've never seen a spur out of round (which was the case for me when I was new to the trucks) the first one you come across will likely strip the "loose" spot. By checking the spur/pinion gap throughout the entire revolution of the spur you avoid this possibility.

Hope that clears it up a bit.
 

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Discussion Starter #11
Wow:
I cant understand how they end up out of round. I would think they are formed in a mold at the factory. I cant see how the mold would become out of round. Unless somewhere along the line the gear warped from heat in the manufacturing processing or elsewhere. Where those problem gears warped in any way. That might cause out of roundness.
 

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no warpage that I've seen. You also have to realize your playing with a very tiny amount of "error" in the gear. Since I like my pinion as close as possible without any binding what so ever, I check the gap the entire circumference. 'IF' there is a tighter spot then I make sure that I have the least amount of gap possible there and the rest of the gear will still be acceptable. Just as you've found a pinion/spur gap that is to wide will make the horrible sound you were dealing with along with slipping. If your gap is to close you could have binding issues which will add much unnecessary stress on the motor and tranny.
 

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I think you'll have a hard time pushing a quality control issue.

There's not a gear mesh I've set in any RC vehicle that was perfect in my 10+ years of racing. The statement of checking the whole circumference of the spur gear's revolution is true. But it's not just the gear. The tranny top shaft, spur gear, motor plate, pinion gear, motor shaft, motor bearing/bushing condition all could contribute to what seems an out of whack gear mesh.

Traxxas Emaxx, Associated, Serpent, Losi, Schumacher, Kyosho. It's not particular to any brand.

Frankly, it's more of loose tolerance of parts, in the given application. (Tolerance is a measurement of how far off from PERFECT a part can be manufactured and still be useable.) Logically, it would seem, the parts tolerance should be loose as possible without compromising performance & durability. Sure, these parts could be held to tighter tolerances, but that would increase the cost of the part. How much more would you be willing to pay for more precise parts, when the ones your buying now work fine?
 

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Gee Mr Hogg, yous be a soundin lik a knowligable type a paerson there, when'd you get so brainy? :freak:
 

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Maximundo said:
The problem is solved.
It was the motor shaft gear and the spur gear out of adjustment.

I was right first!!! Do I win a prize? :lol:

That's OK, I am here in Boston watching the game. that is a prize enough!
 

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ChrisHarris said:
I was right first!!! Do I win a prize?
In theory I was right 'cause all you pede guys showed up and helped out :freak: :lol:
 

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Discussion Starter #18
Invoice from Bedrock

Yea:

Would seen to make more sense that other factors would contribute to a gear appearing to be out of round.
Unless you bought your gears from Fred Flintstone.

Yabadabadoo
 

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Well us Pedey guys get drawn to a 'traxxas" post like moths trying to get our butts burned on a candle. or somethign like that. :freak:
 
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