I bought one of the first 350Zs (#254) and have had the car about 2.5 years and 66K miles. After complaining several times about not being able to shift into 3rd gear they replaced my transmission last May.

In late December I started hearing a noise. It's like a whine/squeal from under the car, sort of where the clutch, transmission are. It sounds to me like a bearing going bad but I'm not an mechanic or anything. The sound only happens when the car is cold. I start the car, can rev the engine, and everything is fine. I then start down the road and hear the squeal/whine when I hit around 40 mph. This will last for a few minutes and then go away. I won't hear it at all again until the car is cold and then driven, which means after work or the next morning. In addition, it was much worse in the cold weather (20 degrees in the morning) and can hardly be heard in the warm weather. The sound is also speed dependent. I can rev the engine while moving and the whine/squeal will remain the same. I can also put the clutch down while the car is moving without much affect on the whine/squeal.

I took it to the dealer a few times and they said they can't hear it enough to diagnose it. They also said it might be the transmission and that I'm out of warranty since I'm past 60K miles and the transmission they put in last May was warranted for 12 months / 12 K miles and I've put more than 12 K miles on it. It seems like a replacement transmission should not go bad in 7 months.

Any ideas what this problem may be or suggestions on what to do to figure out the problem or get it fixed ?