crazy sounds from my tranny....

[outsider]

I was just out bashing with my car (Ultima in an empty gravel parking lot) when all of a sudden my car starts making a crazy sound. Sounds like a cat on speed purring. I took my spur gear cover off and noticed a grain pebble between the teeth on the spur (the plastic spur that came with my kit) and then tried it out. still that noise. OK, so I bring it home for more testing.

Take the motor out and try it. No weird sounds from just the motor. I put it back in. I take the bones out of the outdrives. Makes the sound again. I recleaned everything and tried but no luck. I just rebuilt my diff and checked it. It was still tight. i don't think it was the diff. I inspected the spur and there is some little dmage... i wonder if it's the spur? Any ideas?

[RichieRich]

Outsider - I noticed that if you bolt on the rear wheels too tight on the Ultima, the rear arms can make contact with the inner reinforcing ribs of the wheels. This makes a sound kinda like a cat purring. Try loosening them up a little.

[bubblejunky]

A slightly damaged spur or pinion will make quite a racket.

[outsider]

Richie, I tried with out the wheels and it still made the sound. But thanks for the info, I can probably use it later on.

dc, I inspected my spur gear and it does have slight damage but I thought nothing of it. Where a pebble was stuck on my pinion, there are tiny impressions all along the spur. And also in 2 spots on the spur there are teeth that are flattened by half mm or so. This may be causing the problem. I should get another spur gear to test. Who makes good spur gears? Any associated compatible will work. (not plastic preferably)

[bubblejunky]

Robinson Racing, Kimbrough, etc. They are all good and all plastic and all relatively cheap.

[ChumsGum]

Robinson Racing claims that their "Absolute" series of spurs and pinions are the quietess around.

[ChumsGum]

Robinson Racing claims that their "Absolute" series of spurs and pinions are the quietess around.

[XXXER]

I would get a Kimbrough, the robinson ones are quiet, because they are a pretty soft plastic(that is my observation, at least), not to mention that I have gotten Losi spurs and pinions to run the quietest around.

Kimbrough are beefy, get them.

[RichieRich]

I would replace the spur gear anyways. I didn't like the stock spur - it made too much noise. One fractured tooth on a spur can make a ton of noise.