The indicators on the dash are stating that it is in 4 wheel drive, but it is not engaging. It a 2005 F250 6.0. I found this out on the boat ramp yesterday. HJope its an easy fix.

 

4x4 on the dash indicates the transfer case has shifted and is in 4x4. As for the hub that is a different story.

The rear hub is always locked.

As for the front hub.
If you have manual shift on the floor w/ manual front hub. You just have to get out and manually lock the front hub.
If you have ESOF that means the system is NOT working. You either get the system fix so it works properly or you have override the front hub by manually locking them in.

 

even if the hubs are working properly, sometimes they need to roll a bit to engage properly. Engage 4x4 before you get stuck.

 

The truck is a lariat and does not have the floor shifter. The shifter is on the dash.

So if I put it in 4 wheel drive, I can lock the front hubs in manually and they will work? Is this correct?

What should I look for to get it to work correclty so that I don't have to manually lock in the front hubs?

 

Your truck has ESOF.

If you manually lock the front hub. As soon as the transfer case engage into 4x4 - you will have power to all 4 wheels. The disadvantage of this - is that the front axle will continue to rotate regardelss of 2wd or 4wd. When in 2wd mode this increase fuel usage due to unnecessary gear rotation of the front axle.

As for fixing it. Unless you are mechanical inclined. You need to take it in.

 

Did you go off-roading or in deep snow? You may have disconnected/broke a vaccum line going to one of the front hubs. Does your A/C work ok?

 

I just bought this truck 3,000 miles ago. the truck had alot of mud on the frame rails and where a power washer wont reach unless you lay down to get it out. I havent ever used the 4 wheel drive. When i test drove it, the lights on the dash came on and 4 wheel low worked (at least it did give me low range). Where should i look for the vaccum hoses?

I know understand about the A/C. Sometimes it only blows out the defrost and takes a minute to shift to the vents. I sometimes have to change it to getit to work correctly

 

ESOF, as BPofMD is probably about to tell you, is run, switched into and out of 4X4, with vacumm. Well, the hubs are switched from "Auto" to "Locked" with vacumm. The front differential is switched electronically. Similar to the hubs, the A/C system works, controls where the air comes from, on vacumm.

If the A/C can't seem to make up it's mind where to send the air out of, or, it only blows in one location and will not switch to another, you probably have a vacumm leak somewhere. The A/C problem is often the first question asked because it is an indicator for the vacumm system.

If the ESOF (Electronic Shift On the Fly) 4X4 system is not engaging, though indicated, it is often a result of a vacumm leak. It may be the solenoid. It may be a loose or cracked hose. It may be the rubber O ring(s) in the 4X4 hub(s).

The differential usually engages. But the hubs do not.

Many suggest that you replace the OEM hubs w/ Warn, or similar, manual hubs.

Others suggest that you just use the OEM hubs as manual type hubs. On the hub there is a "Auto" position and a "Lock" position. When you want to, or expect to, need 4X4 simply turn the hubs from Auto to Lock as you would a manual set of hubs. When the need is no longer there, or anticipated, move the hub selector from Lock to Auto. Thereby disengaging the hubs, as in a manual system.

Some will tell you not to bother ever setting any hubs out of the lock position. I suggest that there is a reason for the hubs to have the option. Both for longevity and fuel mileage.

In any event, there is information on this website that explains how to test the system for a vacumm leak. Then you simply have to repair the leak. Then you are back in 4X4 business.

 

Given a choice (new purchase) - I do prefer the manual floor shift w/ the manual locking hub.

Since my truck came with the ESOF instead (preowned purchase). Can you link me to that info - I would like to keep tab on it as regular maintaince to make sure it is always working. Afterall it is a very nice convenience feature. Should it ever fail. I will definitely get it fixed.

 

Here is something I picked up from a forum somewhere.

You may find it useful.

Other than this you will have to do some searching.

A handi site that I have purchased from when doing a 7.3L water seperator drain valve repair is Guzzel's. He also has a repair for the ESOF vacume issue discussed here. The web address is;

http://www.guzzle7pt3.com/allube.php

And now what I picked up somewhere;

Hublock Vacuum System Leak Test
NOTE: This procedure requires the use of a calibrated vacuum gauge that is accurate to within a minimum of 0.1 in-Hg. It is recommended the Pressure Vacuum Module 105-R0099 or equivalent be used.
Make sure hublocks are in the AUTO position.
Lift and support the vehicle off the ground until the front tires can be spun freely. Refer to Section 100-02
NOTE: The engine is required to be at idle during the following steps to supply the vacuum required for the hublocks to engage and disengage.
Start the engine and allow to idle.
Turn the mode select switch (MSS) to the 2WD position and wait 15 seconds. If switching from 4X4 mode, wait an additional 45 seconds.
Disconnect the vacuum line at the right front knuckle and install a vacuum gauge on the line.
Disconnect the vacuum line at the left front knuckle and plug the line.
NOTE: Normal operation applies engagement vacuum for 45 seconds and then drops to 0 in-Hg.
Turn the MSS to 4X4 and observe the vacuum reading. The vacuum reading should remain at or above 10 in-Hg for 45 seconds.
NOTE: Normal operation applies regulated disengagement vacuum for 15 seconds and then drops to 0 in-Hg.
Turn the MSS to 2WD and observe the vacuum reading. The vacuum reading should remain between 5.8 and 7.3 in-Hg for 15 seconds.
Remove the vacuum gauge and connect the vacuum line at the right front knuckle. Turn the MSS to 4X4.
NOTE: The right front axle shaft and universal joint should turn.
Wait one minute then rotate the right front tire one revolution forward and one revolution backward while observing the right front axle shaft and universal joint. Turn the MSS to 2WD.
NOTE: The right front axle shaft and universal joint should not turn.
Wait one minute then rotate the right front tire one revolution forward and one revolution backward while observing the right front axle shaft and universal joint.
Install the vacuum pump and gauge line on the knuckle and pump to 20 in-Hg. If the vacuum drop is not equal to 0.5 in-Hg in 30 seconds, Go To Pinpoint Test G for further diagnosis of the hublock system.
Repeat steps 1 through 13 for the LH hublock. If results are not as indicated, Go To Pinpoint Test G for further diagnosis of the hublock system.
PinPoint G is going into electrical tests. I don't think you need that info for the problem you are experiencing.

 

Thank you and guys like you that take the time to put this kind of reference material on
line, so that us guys out here trying to save a dime can. PRICE LESS