cristian9509

It's been a long time but I've managed to finally bash that Rustler again. However I noticed that there's a nasty sound coming from the spur gear and it's becoming worse by every bash it gets.

I set up the gear mesh as suggested in the manual, with a piece of paper, and there's a weird sound when the gear touches about 5-6 teeth of the spur gear.

I made a video of it and hopefully someone can direct me to the best way of solving this issue.
http://youtu.be/jbJIpH7B-fs

Thanks.

lewis110

iTrader: (3)

Gave you checked the play in between the spur and pinion? I seen you used the paper but its very much possible that the spur isn't perfectly round and is just to tight in a couple spots. If you do find that you still have a tight spot just losen the pinion and just give yourself just a little play is the tight spot.

fq06

iTrader: (12)

Yeah, what lewis said... you can see that spur is not even close to round. Back the mesh off a hair and check it. Keep doing that a hair at a time till it sounds normal. Then look closely are all the teeth as you slowly turn the spur to make sure you have enough contact on all teeth. Normally I wouldn't suggest that last part but that's so out of round that it's probably a good idea.

Is there a aftermarket spur with better tolerances that's not oval?

Edit:
Answer to your problem may have to change pinion size but you will match a new pinion to a new spur anyway.
http://www.jconcepts.net/index.php?/...ls/2824/recent

NHRCRACER

Are you able to isolate exactly where the noise is coming from? I'd suggest disconnecting the axles and listen again (if you haven't already). The Magnum 272 transmission is a really old design. You could have a runout issue, but if there was a runout issue, your trans would have probably sounded like that from the start. Have you inspected the spur gear--each tooth? Also, make sure the pinion is making full contact with the spur (meaning it isn't in too far or out too far on the motor shaft).

pablo040

1 - People often replace a spur gear, thinking that pinions being metal they don't go bad. But it's not true; I've seen cases were pinions get ruined on just one run with a chewed spur.

2 - in addition to what others mentioned about out of round spur gears (this tends to happen more often with cheaper spurs) -- I've also noted, even with the best of brands that literally all molded spur gears are ever so slightly put of round (oboe expensive machined gears are perfect). So I long ago made a practice to find the high spot on all my spurs, barely overtightning the mesh easily allows you to find the high spot, and then marking that spot with a sharpie. Then when I'm setting the mesh, I do so at that premarked spot. It's been my experience that allows me to get the smoothest mesh possible.

I Wheelie A LOT

iTrader: (15)

Have you tried checking the spur for missing teeth or a small rock stuck in between them? I've had the same problem with my stampede before, and It was usually the case of a stripped spur. I would use a small flathead, and just rub it in between every tooth, and see if that solves it. Good Luck.

LOSIMANJRXS

iTrader: (29)

It almost looks to me that the top shaft is bent, Watch the rotation of it in the video, you can tell by how far off the spring is spinning

cristian9509

The spur looks perfect. There's nothing wrong with it like missing teeth, chewed teeth or anything else. I localized the problem teeth, about 5-6 of them, and have them marked with a sharpie. I think the spur is just not perfectly round and those teeth have a bit more plastic on them. I will use your advise on setting the gear mesh with the paper exactly where the spur teeth are higher and see what happens then.

Right now my gear mesh is set by loosening the motor screws, giving it some steady throttle, and moving the pinion from the spur until the nasty sound is no longer there. The ride feels more smooth and the sound coming from the car at low speed is much much better.

Next thing would be to sand a little between the problem teeth and see what happens.

cristian9509

The shaft does not look to have anything wrong. The spring cannot be centered perfectly and I don't think that you can judge the shaft by the rotation of a spring. I think the eye can be fooled by the rotation of the spring. It's an not perfect round spur, as pablo says.

From now, I would use his suggestion of checking the highest point of the spur and then set the gear mesh in that exact location. Works like charm! Just tried it now and it works!