I first noticed towards the end of winter, if it was too cold it wouldn't engage in 4x4. As the days got warmer it worked fine.
The last time I use the 4x4 was about a month ago and today I tried it and it would not engage. No lights and no 4x4 HI or Low.
As I pull the lever I can hear clicking and feel the clicking holding the stick but after a min it stops clicking and doesn't go into 4x4.
Thoughts?

 

Near as I can tell your floor shift control.
Sounds like the transfer case motor does not rotate for some reason.
It has to move to the first position to put case into the drive train, and closes through operating voltage to the firewall solenoid.
The firewall solenoid transfers vacuum to the front axle actuator that slides a collar to lock up the front drive.
When this is complete, the dash light comes on.
You have to find out where the sequence stops.
Good luck.

 

Thanks for the reply, although this was way over my head
Lord Jesus, I may have to bring it in.

 

What I didn't include in the short discription was a module called a GEM that conducts the whole show.
Since you heard clicking I assume the module is likely to be good trying to get the rest of the sequence to work, then times out.
It takes some effort to check out and see where is fails if you do your own work.
The transfer case motor turn a shaft to bring in the case and drive the front drive shaft.
In the motor housing is a circuit board that has brush contacts that operate the other function, so you can see if that dosn't happen then the 4wd does not engage.
At least you have some idea what all has to happen to make it as easy as it normally is.
Good luck.

 

So Bluegrass, If the front axal will not engage ( Due to the Acuator on the front diff) will the tranfer case go into 2low, Like the older trucks would if you did not have the hubs locked?

 

A fault like that, you would not know if it did or not if the front axle is not locked except by feel.
Two things happen in 4L.
The transfer case goes into gear reduction for both the rear and front drive, and the case motor signals the PCM to change the shift sked to keep the motor from winding too high in RPM, before shifting.
Actually one could play tricks on the system and get 4L position to drive just the rear wheels without the front locked up, if that was ever a useful application.
Good luck.

 

Does the transfercase go into 4Lo? This is important to know to further diagnose the problem. Easy way to test: shift into 4Lo and drive. If the truck moves at a slower than normal speed for the RMPs then the t-case has shifted into 4Lo.

 

I tried 4lo and the truck did drive in low gear (slow) but the 4x4 didn't engage because my rear wheels was spinning and the front didn't do anything.

 

Starting at the actuator, the lockup collar did not engage, the actuator did not operate,or the firewall solenoid did not operate.
There can be a set of circumstances where what you have will happen.
Think it through and look a those parts I mentioned for operation.
Good luck.

 

This is a good thing. It means that the transfer case is shifting. Look for a connector on the front of the t-case near the breather. Unplug it and check it for Corrosion. Short both those pins on the wire side connector to ground. Your 4x4 Lo light should come on. Shift into 4x4 Lo and see if truck is in 4x4 Lo
If it is then you need a new switch.

 

Ok Guy's, here's the scoop! I (just for ****s and grins) tried spraying the connector near the 4x4 shifter assembly with electronic contact cleaner and than sprayed some fluid film over it. Tried the 4x4 and it worked on hi and lo.
Now with that said, I drove it down the road and all of a sudden the 4x4 was trying to engage for no reason.
Guess I need to disconnect it and give it a good cleaning.
Ok is there something more I should be doing in terms of cleaning/product?
Oh and BTW, thank you all for the help.

 

I would use Mineral Spirits or Denatured Alcohol and compressed air. You can use elec contact cleaner, but most of those leave a residue, even when they advertise "no residue". So you end using spirits anyway, IF you want them really clean. The best contact cleaner I've found was at Radio Shack, but it costs $12. Compressed air to assist is a big help. They have to be dry when reconnected or your risking further damage, like back-feed/surge and whatnot. Just make sure it's dry and whatever you use is plastic safe or you'll have more problems.

It wouldn't hurt lubing up your actuator pin as well. It's better to do this w/mighty vac tool so you can work the pin in and out. Your remove the Pink and Blue actuator vac lines @ the actuator. Remember how they attach correctly because the Ford Service diagram is backward on some model years. With the vac tool, you alternate ports which moves the pin in and outward while lubricating. The do freeze up and at service, the actuator is usually ruled out first. Not saying that's your problem, but it could be. Or it could be a contributing factor if it's half way froze up.

 

Do you mean the switch on the transfer case? If so then cleaning it might help but it works by shorting those wires to ground. In 4Hi it shorts one then for 4Lo it shorts both of them to ground. You may have accidentally shorted the wires to ground with your cleaning. A new switch is 30 bucks at Rock Auto.

 

Cleaned and free'ed up link on front dif area. 4x4 is now working great...although light stay's on.