Hi, I’ve been having issues with my 4x4 system on my 2011 f250 6.7 powerstroke. I just bought it recently and the 4x4 seemed to be working fine when we got our first snow, but now it’s hit or miss. It seems to work when I first shift into 4x4 high and low and it works for a bit, but then goes back into 4x2 and says “check 4x4” on the dash. It also seems like it revs higher, but doesn’t deliver all the power, but it might’ve just been the conditions I was in or just how the truck is. (This is my first Ford diesel) My buddy said something like that happened to his 6.7 and it turned out to just be a sensor. (All testing was done with traction control off and the lockers on auto) The truck only has about 92,000 miles.

 

Do these Super Duty trucks use a vacuum operated hub system like the F-150? If so, you'll need to check the vacuum lines from the hubs all the way to the junction on the firewall, as well as the operation of that solenoid that controls everything. If no problems found there, it could be the 4x4 switch on the dash.

 

The vacuum system for engaging the front hubs is problematic. Cracked hoses, leaking seals. You can always select manual at the hub when needed. Hubs not working doesn't trigger a message on the dash though. My guess is you have an issue with the servo motor on the transfercase.

 

Yea, sounds like a transfer case issue.