Mazda 6 2006 Problems

Mazda's maintenance schedule suggests that the fluid and fluid level be inspected every 20,000 km, so the dealer has done the right thing and checked yours at the appropriate service. He's also done the right thing in warning you that it could need changing at the next service, and given you a possible cost. Some automatic transmission specialists, those of the old school anyway, are adamant that the transmission fluid should be changed every 20,000 km to keep the transmission alive and well. It would seem the dealer has given you good advice on the possibility you might need to change the  fluid, although the cost does seem a little high. Ask the dealer for a breakdown of the costs so you can see what the fluid costs and how much time you're being charged for. That should tell if you are being overcharged.

In a sense you've already answered your own question. You have used 91 octane without a problem. The Mazda 6 will cope with the lower octane but will run at its best on the fuel with the higher number.

ALL wind noise is aerodynamic and can come from many sources. It's the result of air being disturbed as it flows over the car. Wing mirrors are a common cause and nothing can be done about it, unless they are damaged and the damage is causing the problem.

IT MAY be that there was a batch of problem discs fitted in production because the problem does seem to be widespread. And fitting new discs at such low mileage is unacceptable, if that is the norm with the Mazda 6.