Transmission noise G35 Coupe a/t

[jakg35]

I've got an '06 G35 coupe with a/t and approx. 4,500 miles.

For the last month (roughly 2,000 miles) there has been a grinding noise that is approximately two seconds long and always occurs just before the transmission shifts from first into second gear. This only occurs on a cold start and it only occurs once. In other words, if I come to a full stop and then accelerate again, this noise is not present. However, if I turn off the engine for about five minutes and then restart it, the same grinding noise will occur again immediately before shifting from first into second.

Other than this noise, the transmission seems to work just fine. I have tried to determine whether this is being caused by another system (steering, brakes, etc...), but it always occurs just before the car shifts for the first time.

How can I best describe the sound? It sounds almost like a giant rusty spring that is being compressed, or like one of those spring loaded stretch bars that people used to use to work out with in the 70's, not that I would know. Just kidding on that.

Thanks. -John