I have a 96 2500, when I engage the 4X it will go in, but once I get up around 25mph it starts to make noise and vibrate, It sounds like it is not locking up completely. I have installed a new actuator but have the same results. I have also engaged it with the actuator out and it does extend. I have 2 questions, 1st how far does the actuator extend when engaged? and 2, where can I get a detailed view of the differential? I would like to know exactly what goes on when the actuator extends to actually engage the differential. Thanks for the help!