I have only owned the truck a few months so have only used four wheel drive a couple of times. On previous try it seemed to take a long time to engauge. Monday during the snow storm here on east coast it did engauge and after driveing about six miles I stopped (never cut truck off) and when I took off the front wheels were no longer engauaged. This is 2004 F150 Heritage, when I shift the shifter into 4H the light always comes on and stays, but I don't hear or feel anything and then the four wheel drive would just start to work. After doing some research on this site I found where the selnoid on the firewall behind the battery could be the problem, and being my is the old style with no cover I was going to replace it. When checking on this I have found there are two side by side on the firewall and they appear to be the same. Do I need to replace both of these or what should I do? All the pictures I have seen here or anywhere else only show one selnoid. Also I never hear any noise grinding or other from the front wheels at any time. I bought this truck for the four wheel drive so I'm really not happy but so is life.

 

Only one thread per subject allowed, so I had to remove the second thread. If you want this one moved, just PM me and I can move it for you.

 

If you have a 2004 Heritage Edition truck, it's basically a 1997 - 2003 F-150. That truck has a completely different four wheel drive system. Disregard anything you read on the issues & fixes for 2004 & up trucks.

 

I had that issue in my 02. Probably a bad vacuum solenoid. I replaced my and the issue as gone. It is a common problem. I think one locks and one unlocks the hubs, probably should do both.

 

You don't have hubs, you have a differential lock.

 

Ding, ding, ding. We have a winner. That's the big difference with the pre-2004 trucks.