So this isn’t the first time this discussion has come up on the Toyobaru Facebook group. “Red Guy” claims to ‘work for Toyota’ and has insisted to people on multiple occasions that if they use any brand of motor oil other than the factory brand, that they will void their warranty. Same for the transmission, and differential, and presumably any other fluid in the car. I would assume, then, that he might say the same about using different wiper fluid...

Since he doesn’t seem to believe the three or four of us that try to tell him he is wrong, and that whatever dealership he works for is doing something that is straight-up illegal, I figured I’d post the question to the Oppo community to see if people could give us a definitive answer.