Transmission rattle anyone?

I have noticed an increase in the amount of times my transmission seems to give a quick rattle noise whenever I take my foot off the gas. I have absolutely NO reduction in performance. I love my V6 SEL - the thing flies, has smooth shifting, and is a wonderful car. Gas mileage is even beginning to come up....I was getting 13-15mpg on average but it is now like 18-20 now that it has 7,500 miles on it.

The rattle part just bothers me because it seems to be something that is almost increasing in frequency and just about happening every time I take my foot off the gas. The rattling noise can last from a split second to 1-2 full seconds. I do not notice the same rattle whenever the car is NOT in drive and I rev the motor.

Does anyone else have something like this that they have addressed with their dealer? If they have, what was it? I dont think it is anything major, but it is starting to get on my nerves.

Thanks,