I'm having a problem with 4 wheel drive on my 2003 F250. About two months ago my mechanic greased the hubs for me because I was having a problem while in 2 wheel with turning and hearing a clicking noise. It seems that everytime I put the truck in 4 wheel drive something is keeping the drive engaged after that? After going back to 2 wheel drive I keep hearing a clicking noise from each wheel, when I make left or right turns, as if the unit was still engaged. I forget what the mechanic did last time, but he lifted the truck and spun the wheel and the axle was still spinning. I forget what he did to disengage it but what would cause this to happen everytime I use the 4 wheel drive? I keep my hubs in the auto mode and have never moved them from this position.

 

ESOF? Or manual?

Edit.... Oh, auto mode

You may want to check the vacumm hoses down at the axles for cracks and/or holes. Lack of vacumm will cause engaging and disengaging issues.

You might want to seach ESOF vacumm issues.

 

How much grease did he use?

The hubs should be cleaned and greased very lightly. A thick coating of grease will hinder proper ESOF hub operation.

If this isn't the problem, a vacuum leak will also cause the issue. When you turn the **** from 2H to 4H, does the heater automatically switch to defrost mode? That is a classic symptom of a vacuum leak.

Lastly, the hubs themselves may just be fried. Replacing the ESOF hubs with MM or Warn manual hubs is a popular modification.

 

My heat automatically switches from the floor to defrost at various times while in 2 wheel drive, normal everyday driving. This has been happening for the last few months. Also, I notice that when I'm driving on the highway, the heat will switch to the defrost, if I let off the gas, it will go back to the floor heat. It does go back and forth though.

Where would the vacuum leak be? Am I doing damage to anything?

 

Check the vacum lines behind the rotors for cracks and holes. Those locations get a lot of movement.

 

Thanks guys for the suggestions. I'm not a mechanic and have a few more questions. I'm not sure if most mechanics know much about 4 wheel drive systems, but I'm surprised that my mechanic didn't pick up on this?

Anyway, here's my questions:

What's ESOF?

What does the vacuum lines for the hubs have to do with the heat? I'm really glad it was mentioned because I've been having a problem with the switching of heat from the floor to the defrost mode, eventhough the heat switch is set for the floor and I'm not using the 4 wheel drive. The heat thing happens everyday and will go back to the floor when I let of the gas. It's intermittent.

Is there any damage being done driving the truck like this?

I'll discuss with my mechanic about the thin coat of grease as well as the vacuum lines.

 

When you have enough vacuum your heater will stay on floor forever. When you develope a leak the system has a hard time keeping up I/E hub leak. When you push on the gas the engine makes less vacuum and when you let off it makes alot..You have a leak. Find it fix it and you should be fine as long as your hubs are ok.


Dick

 

E lectronic
S hift
O n the
F ly

ESOF is a system that uses an electronic solenoid to control vacuum to switch the hubs from free to lock. There is a rubber tube behind the front rotors. That is the one the vacuum goes through to the hub. One on the right side and one on the left side.

The heat distribution system is also controled by a vacuum system. When the vacuum system goes bad it effects those systems as described.

If you have a need for 4X4 rotate the hub from Auto to Lock. That will over ride the hubs and they will be in 4X4 when you turn the inside switch from 2WD to 4WD Hi or 4WD Low and then out of 4X4 when you switch back. Like a manual 4X4 system.

Here is a test procedure I stole off the forum earlier today. You may want to show it to your mechanic....

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.

 

Thanks for the explanation and the test procedure, I will share it with my mechanic.

Question about the hubs, you mentioned to overide them by going from Auto to Lock. You mentioned that this will over ride the hubs, I'm confused by this. What's the difference between the Auto mode or the Lock mode? I've never moved them from the Auto mode. When I use 4 wheel drive I just put the truck in neutral and move the switch from 2wd to 4wd, high. I guess I don't understand the difference in the two modes on the hubs and how it relates to the switch inside. Does the lock mode keep the axles locked in 4 wheel all the time?

 

"Does the lock mode keep the axles locked in 4 wheel all the time?"

When you set the hubs from Auto to Lock you over ride the vacuum system and lock the hubs for 4X4 use. Similar to a manual system.

On a manual system you have to set the hubs from Free to Lock. When set to Free you can shift into 4X4 hi or 4X4 low all you like and still not have the wheels engaged for traction. For 4X4 in a manual unit you have to set the hubs to Lock AND shift into one of the 4X4 ranges. Typically, when one does not have a need for 4X4, you set the manual system hubs to Free and shift to 2WD from whichever 4WD you are in.

With ESOF you do not have to get out of your truck, walk around to each hub, and set them from Free to Lock. With ESOF you simply turn the switch. The truck does everything.

With ESOF, if you do set each hub from Auto to Lock you have the hubs locked and ready for use similar to a manual system.

I see no real need to set the hubs from Auto to Lock with ESOF unless the vacuum system fails and you need to over ride the vacuum system. To be able to do so is a nice backup feature in the event of vacuum system failure.

 

Ok, let's see if I get this? With my ESOF setup:

I can leave the hubs in the Lock position and still use the 4 wheel drive like I normally would. Put the truck in neutral and switch to 4 high. When I'm done, neutral and then back to 2wd.

This is the same procedure as if I had them in the Auto position. That's what doesn't make sense to me.

I guess the difference is that the Auto uses vacuum and the Lock doesn't? What's the advantage to having the Auto setting, wouldn't it be better to just leave them in Lock position? I'm going to put them in Lock and over ride the vacuum to see if my heat stops going from floor to defrost? Will this clear up the clicking noise I'm hearing when turning?

 

"What's the advantage to having the Auto setting, wouldn't it be better to just leave them in Lock position? I'm going to put them in Lock and over ride the vacuum to see if my heat stops going from floor to defrost? Will this clear up the clicking noise I'm hearing when turning? "

The advantage is simply that you do not have to do anything other than turn a switch to enter and leave 4x4 operation.

I have been doing 60mph on the freeway when, suddenly, there is a strong cross wind on a stormy night that pushes the Excursion one way or the other. I simply turn the switch to 4WD Hi and there I have it. 4WD stability and control.

A few weeks ago I left California for Montana via Nevada and Idaho. A major storm came in from the Pacific Ocean and pushed it's way across California towards, and onto, the Sierra Nevada mountains. As we, my wife and I, assended the mountains and the rain became a snow storm, the roads became icy, the traffic was being pulled over in the cold, wet, slurry to install chains I continued on in my warm truck. After a while I had to move from a plowed lane to a non plowed lane to pass slower moving vehicles. As I moved into the 10 or 12 inch deep snow I turned the **** and went from 2WD to 4WD Hi. Once we went into Nevada and the storm was behind us I simply turned the switch back to 2WD.

I believe that in your owner's manual you will find that with ESOF you do not need to stop, put the tranny into neutral, then make the switch to, or from, 2WD to 4WD Hi or back. YES, you do for 4WD LOW. But, to and from 4WD Hi it is just a matter of turning the switch. That is how I use it and how it is explained in my owner's manual.

My owner's manual says;

Shifting from 2WD (2WD High) to 4x4 HIGH (4WD High)

Rotate the 4WD control to the 4x4
HIGH position at speeds up to 88
km/h (55 mph).

•

is moving.

 

If you need one you can download an owner's manual and other asociated manuals from;

https://www.flmowner.com/servlet/Con...OwnerGuidePage

It will have instructions for use of your ESOF.

 

No, no exactly.

The front hubs are mechanisms that connect the front wheels to the front axle. When they are in free wheel mode, the wheels can roll but the axles to do not. When in locked mode, a mechanical connection is made and the axles turn with the wheels.

OK, so if your ESOF hubs are working properly, when you are in 2H the wheels spin as you drive down the road, but the front axles and front driveshaft remain stationary.

Shift to 4H, the hubs lock and the transfer case engages. Power is transmitted to the front drive shaft, then through the front differential to the front axles. The axles are connected to the wheels (because the hubs automatically locked) so the power goes to the wheels and moves the truck.

If you lock the hubs but leave the switch in 2H, then the wheels are connected to the axles. When you drive down the road the wheels will spin the axles, which will spin the front drive shaft through the differential. The transfer case is not engaged, so no engine power is being applied to the front drive shaft. It will spin freely.

There is no need to stop, put the truck in neutral and then shift to 4H or back to 2H. You can do that while driving down the road. You do, however, need to follow that procedure if you want to shift into 4L.