I have a 2000 Yamaha Kodiak and the 4x4 servo motor will not lock into 4 wheel drive. I can hear the servo running but as soon as you take off you can hear the servo disengage. I have read the posts about servo motors but I don't think the servo is bad since you can hear it engage. Does anyone know if there is something that keeps the servo motor engaged? Or if it is the servo does anyone know where not to spend $300 on a replacement?