New TS 242 question

Guys i have 1 more problem i am not sure if its a problem at all, but seems that my husq. have some strange grinding sound when i release the break. Mower have 3 hours of mowing atm and this sound is here from start ( new tractor ). I checked on other forums and seems i have problem with tension of belt at hydro transmition.

So when i start with minimal throttle there is no sound. Grinding sound appear when i put throttle in middle position and disapeare again on full throttle. Sound disapeare if i press break. Mower is new, so i wonder if i should give it back to the dealer - warranty?

Here is a video. At the end u can hear that sound realy clear.

https://www.youtube.com/watch?v=YZZFuXYmppg

Tnx for help

That is the sound of your belt running and probably the back of the belt rubbing on the steering shaft or even a belt keeper.
Pull the deck off, get under the mower with some one else on it and watch the belt as the brake is applied & let off.
The brake pedal is both the brake and the clutch and the clutch works by releasing the tension on the drive belt.
Belts make noise when they run over pulleys.
With the brake engaged spin the idler pulleys by hand and check that the pulleys turn freely.
The mower does not sound bad to me but you might just have a bad pulley