Derf

TSB #3237 -- 700-900 RPM BUZZ MOAN RATTLE RESONANCE NOISE ON ACCELERATION.

This is minor, but annoying. Does anyone have this TSB or a fix? Thanks

JetMechZ16

My 04 Z06 CE has a resonance/rattle in the exhaust on cold startup. Once it has warmed up it goes away. It is annoying and embarrassing when in public. I haven't as of yet tried to remedy this. I need to put it up on ramps and get under there when it's started to pinpoint the area.

Let me know if you find any fixes. I've heard it's a continuing problem.

Derf

Two trips to the dealer for this moan/resonance noise so far. Going back next week. This occurs at 700 - 900 RPM. The exhaust has been changed with no change in the moan. Sounds like it's coming from the trans area. Any help would be appreciated. The vette runs great other than it moans a lot.

martysauto

Googled it, found it in 30 seconds.

http://www.chevroletproblems.com/tsbs/Corvette/2004/

Cybermind

I cannot find a free copy of the full TSB.

Is this regarding the exhaust jingle or the marbles-in-a-can sound emitted by the manual transmission on 1st gear?

If you're referring to the exhaust jingle, it is caused by the poor design of the factory H-pipe crossover holes. The only fix is to replace the factory H-pipe with an aftermarket X-pipe. I had this problem and eliminated it once I replaced my H-pipe with a Corsa XO-pipe.

If you're referring to the noise emitted by the tranny when you slowly accelerate in 1st gear, there is no fix. The noise is normal and cannot be eliminated. This was also documented by GM in the owner video. It has to do with the fact that the tranny is mounted in the rear right before the diff. This setup has an accumulated mechanical "slack" (shaft/gears?) that gets taken up once you begin accelerating. It is more prevalent the slower you accelerate. Giving more gas as you release the clutch pretty well eliminates the noise.