If you can get to the controller easily you may be able to open it up. I have opened several and found lots of lint and dust, and dirty contacts also, which I clean with QD Electronic Cleaner or very fine grit sandpaper (280).
You may able to clean up the motor as well, especially if it's external, which I can't tell from the pictures. Some motors will come apart easily, others not so much. Either way I use the QD on what I can readily, or the fine grit sandpaper to remove buildup if I can get to it (wash down with the QD after the sandpaper). You can maybe get fresh lubricant to the motor shafts also (I'm sure there are threads about the best lubricant). You have to be careful with the carbon brushes on removal and reinstalling them, they are kind of fragile, and can be hard or impossible to replace. I have dropped out a couple of internal motors just to use the QD where I can.