I'm the owner of a brand new Mazda 3 Skyactiv-X MT with less than 500 kms (300 miles).

I've noticed that when I release the throttle while in 4th gear the gear stick itself vibrates in a very noticeable way and emits a 'buzzing' sound. It only happens in 4th gear and only when I release the gas pedal, not when accelerating. The vibrations are tied to the RPMs and not to the vehicle speed, reaching their peak slighly below 2000 rpms.

I'm going to bring my car to the dealer to make him take a look at the issue in a couple of days, but should I be worried that it could be something bad, maybe related to a faulty transmission?

Thanks in advance for any input or advice.