4X4 Low doesn't disengage sometimes....
 

2005 FX4 5.4
The 4x4 high doesn't have any problems, but when I put in 4x4 low, it doesn't disengage. I think I'm doing everything correctly. I have to turn the engine off and restart for the 4x4 to disengage.
Anyone else having these problems?

Is there anything in the manual about backing up for 10 feet, or other consideration? If what you describe solves the problem, it may just be a procedural issue.

Proper procedure would be to stop the truck, put the transmission in neutral, shift out of 4x4 low until the light goes off, then put the trans back in drive. Make sure you put it in NEUTRAL:thumbsup:

and hold the brake down, for 4low to enguage you have to be holding the brake, might also help to hold it when trying to get out of 4low

Not help, it is required to be in neutral to shift in or out of low with ESOF. Working third brake light too.

Adrianspeeder

:thumbsup:

I have an 03 and it is doing the same thing. Still haven't figured it out yet. I have done everything listed here as well as in the other "4x4 is not working" thread.

https://www.f150online.com/forums/sh...d.php?t=293031

Here is what goes on to get into 4L.
The GEM control module is the prime controller.
It needs input from the switch, the neutral safety switch and the brake off normal signal. It is set up this way to prevent you from trying to engage 4L while on the move.
The switch also operates the transmission electric motor to set up the trans for this mechanical function.
At one of two relays on the fire wall will pass vacuum to a diaphram motor driver on the front axle.
Along with all this, the PCM program changes shift skeds for this operation.
The keys to it are to be in neutral, foot brake applied, switch to 4L, motor running.
Operating the switch into and out of 4L should hear the front axle vacuum motor clunk in and out.
If you don't see any of these actions happening, it tells you about what function is not happening and where to begin looking at the problem.
key is knowing how the system work first.
I have a low stall diesel convertor in my custom built 4r and 4L is like a bull dozer and have to ride the brake putting it in gear or it will pull hard right off idle.

Your talking about the grinding noise when trying to diengage, correct? Someone said it before, you need to try backing up 5-10 feet and try again. Usually it means something isn't meshing very well. This happens to me sometimes and backing up is the fix almost everytime. Sometime you just gotta shut th etruck off and shift it then. Just my 2 cents...

The suggestion for backing up a few feet only pertains to manually locked hubs.

These days, with the switch on the console, it's unecessary.

CRF250 gave the correct procedure.

Bluegrass gave info of where to start looking.

The electric motor on the transfer case sets up the internal gear change to get the total drive gear-down, into 4L.
The vacuum motor on the axle puts the front into lockup for both 4H and 4L.
Any grinding is signs of a problem. Either in the tranfer case shifting or at the front lockup. Can't miss telling which it is, by sound and feel.
Go back and read my reply and use logic to see what, in the flow of operation, is having a problem.
There are vacuum lines involved with the front axle lockup, solenoid valves on the fire wall, motor on the tranfer case.
The lamps you see are lighted from the GEM module after feed back from the tranfer case motor tells the Gem the operatoin has been completed.
The front axle operations don't give any feed back so you detect a fault by how it acts.
As you set with motor running and put into and out of 4L, you should hear the heavy clunk.
Many owners go for long periods of time without exersizing the 4x4 and have a problem when it is used, one day.

Now that i think about it... i think what happens is I will be in 4 lo. Then switch to neutral... then when I try to put her into 4hi it makes a grinding noise and feels real bad in the shifter (note* I opted for the manual floor shifter vs. electronic switch) If I roll around I can usually click it into 4 hi... otherwise i just shut her down. Any ideas?
And FYI backing up is not "just" for manual locking hubs. The first automatic locking hubs made you roll back a few feet to disengage the hub before returning to 2wd :thumbsup:

/\ this is true. Our old explorer had the new at the time push button 4x4 and you had to pull over and reverse apporx 10 feet for it to disengage.