I have a 2003 FX4 Supercrew and I have seen a few these posts on here about the 4X4 not engaging but when we put ours in 4x4 the light on the dash comes on, it makes the click noise and sometimes it is in 4x4 and sometimes it is not. It is kind of an optional 4x4, but never seems to work when you need it to! Any Ideas as to what the problem is??

 

mine does the same thing mines a 03 supercrew its getting fixed in the next week. A freind of mine is a ford machanic and the problem is the shift fork in side the front diff. the part is about 150 bucks its about 1100 to fix cause you have to drop he fron end out of the truck. mine went out on a snow covered boat ramp last year when it started to mess up

 

Thank you, guess we will start there!

 

Or you could have a vacuum leak somewhere causing the 4x4 only to engage sometimes. I had that problem with my old 97 and it was just a vacuum hose. Might want to start there first. Otherwise it is in the front end.

 

Could also be the vacuum solenoid that operates the front diff.

 

I have a 03 fx4 crew also and have been trying to fix mine for over a year now.Someone told me it was my GEM behind the fuse box.Iwas also told there are relays behind the gages.No one ever mentioned vacum hoses and now im wondering if that is all it is.I'm doing some work on it tomarrow and will check the hoses.I will let you know if it works . Thanx for all the great advise this site rocks.