I’ve searched and can’t find any answers but, I bought a used but never used 3401 about 6 months ago. I have put several hours on it but, it hasn’t been abused. Picked it up the other day and no matter which speed setting it’s on, it will go fast/slow, fast/slow. I blew it out with air and took handle apart just for inspection. Looks new and like nothings outta place. Anybody ever ran into this? Thanks