Some days when I take the 350z to school, I will start the car and start backing up out of the garage. While I'm backing up, there is a short, loud buzzing sound coming from the transmission, and it repeats maybe 2 or 3 times at the most. I just shut off the car and start it back up again, and then it is gone. Is this something I should be worrying about? It doesnt affect normal everyday driving, however it just doesnt seem like a normal sound that should ever be heard.

 

What kind of transmission is it? Also, knowing the year and mileage might help. Any other symptoms? Any mods on the car?

I wouldn't bother shutting the car off if the noise goes away by itself and there are no other issues.

 

Does it usually last about a second and happens about 20-30 seconds after you start the car? Does it occur about the time you step on the brake pedal? If so, then it's the ABS self test.

 

my brother and i both have 2003 Z's that do the samething we pay it no mind 0_o

 

Its a 6MT, 03 with 90,000 miles. And yes Dave, it does

 

The sound from the ABS self-test comes from the left front of the car, not the transmission. It's one continuous sound that's not repeated. If you turn the engine off, then start it again, it will happen again.

That doesn't match the OP's description very well at all.