does this tool have metal or plastic gears?

Most the newer tools will have plastic gearing since as the gears wear they tend to break off small bits of the gearing material. If you have metal gearing then those parts get in to the motor and short out the brushes or bind up the bearings. With todays plastics they are every bit as dense as some of the softer metals and perform the same job as metal with out the other hazards. Hope this helps.

Without opening it up and voiding the warranty, my guess is that it has metal gears. Having cannibalized Makitas in the past, I never found plastic gears as they would melt from the heat. The same should apply to the oscillating tool because it builds up some heat, so plastic would not be practical. The power with which it operates and the stress it can be put under depending on the material being cut, and the ease with which mine cut, when I could get it powered up, leads me to believe that it's all metal.