I know the title does not make sense, and I am having trouble in defining this, but here is the case. When I slowly increase speed, a buzzing sound (almost seems like an electric whistling sound) comes from the engine compartment direction. It only happens around 1700rpm to 2000rpm. It stops after 2000rpm.

I only does it in D. I tried it in P, N, and R, and it does not happen.

It is coming close to the end of extended warranty, so if this is an indication of an upcoming problem, I would like to get it fixed now.

It seems so interesting that the sound only happens between 1700-2000rpm. I wonder if it has something to do with transmission.

Thank you in advance for all you suggestions.