Another 4x4 thread... Chicago winter is going to kill me.

[Brett.Bathey]

So my 4x4 wont engage at the switch on the fly or when I manually lock the hubs (I have a 2002 Ford F350 7.3l diesel). I changed the vacuum lines going to the hubs and nothing. My vents before changing the lines were stuck in defrost and after changing the lines they still are stuck. When I have the hood open and the key in the ignition when I switch the air vent controller I can hear the solenoid trying to switch over. The compresser is working too. I there has the be another vacuum leak somewhere else but where could it be? Remember, even when I MANUALLY lock the hubs at the axle it still will not engage. The lights on the dash will come on for 4x4 and I can hear the transfer case switch over. Thanks guys.

[stumpman234]

I have the exact same problem with the only difference being I have a 2000. Went to use the 4X4 yesterday to plow and the lights indicating 4X4 high and low both will come on but not lock the hubs. I then tried manually and still nothing. Monkeyed around with it trying different things but no luck. Brought it into Merlin's for them to look at. They called me and said they found a vacum leak to the hub and were changing the seal. I am waiting for them to call back to let me know that that was the problem. I will let you know if and when they get it fixed. I don't know how the system works but you would think that if the electronic 4X4 did not work, if you locked them manually it would work but no they didn't.

[stumpman234]

OK...got my truck back. Only cost me $202.00. One of the hub vacum seals was leaking. They replaced the seal and now everything works! Good Luck on your repair. They said they used smoke in the line to find the leak. It took them some time to locate the problem. They had the truck since yesterday morning.

[Brett.Bathey]

Do you know how the got smoke into the lines? And when your hubs or dash switch wouldn't engage, we're your air vents stuck in defrost mode even if it wasn't on defrost?