Here it is snow and when I placed my super duty into 4 wd nothing. Hubs set to auto. When I place hubs into lock the the 4WD works fine - any suggestions on why hubs are not automatically not locking - I tried all the normal proceedures and 4WD at front axle not working - transfer case fine I have a 2002 f250 4X4 super duty powerstroke

Easy fix, just take off the factory hubs toss them in the nearest garage or clean them if you want the same probleam again and buy a set of Warn Premium's. Best $200 you can put into your truck.

I had the passenger side fall off one day and the driver stopped working for months on end. Used to have to use a vise grips to turn the hub! Now it's one finger!

The problem is a vacum issue. The ESOF works off a vacum. I have read the most common place is on the passenger side up under the dash. I guess this one gets kicked off all the time. This is my first time on this forum, been hanging out at Dieselstop.com which is just for the PSD's and there are tons of posts over there right now on this very subject. First snow and all the problems show up. Good luck, sorry I could not be more specific, but I am sure you can find other areas to check by looking at dieselstop.

Kevin L.

This Tech Note on vacume issues came from flatrate.com.Vacuum Pump Inop or Ventilation System Deverts to,or Only Blows Through,
Defrost Vents:If the vents devert to the defrost mode,
this is usually due to a leak in the vacuum system.
Typically if the problem is in the automatic hub system,
this will only occur when 4X4 is selected.
If it occurs on in a specifc ventilation mode,
the vacuum servos associated with that selection would be suspect.
If the ventilation system stays on defrost at all times,
a leak in the system at the vacuum pump,
or the vacuum pump itself may be at fault.
For vacuum pumps that are inoperative or continuously running,
replace with P/N 4C3Z-2A451-AB. Broadcast Message 1244, 1575, 3278;
TSB #04-16-08