Superduty “4×4 not engaging” problems? This is a very common issue, here is how to fix it. It might be a quick patch/replacement of a vacuum line, or a solenoid replacement. I made a quick video that will only take a couple minutes for you to figure out what the problem is, and depending on the problem, the actual fix shouldn’t take you more than 15 minutes. When I had this problem I couldn’t find a good resource to troubleshoot, so hopefully this helps. First, is your vacuum pump working? You will hear it when you turn the truck to ON and engage 4wd, you disconnect a vacuum hose (pump senses drop in pressure and tries to re-pressurize), or if[…]