I have a 4X4 F-150 Ford Truck, I was in 4 wheel and the truck shut off, then I re-started the truck and started to drive away it made a heck of noise "grinding" I took the truck out of 4X4 and drove home. The next day I noticed I no long have any high/low 4X4. Where can I start to look for issues?

 

GEM module. Disconnect the battery and let it sit for 30 minutes. hook it back up and see if 4wd works. If it does you need a new gem module, along with having the front windshield resealed.