With all the talk of the failure of ESOF, I decided that I better start using the "lock mode" on the wheels to keep everything kosher. I have 25,000 miles on my 02 and after I locked the front, the next day I am hearing a mild clunk noise during full radious turns. It is almost like turning on dry pavement with the 4x4 on but with no pulling and tire hop. The 4x4 still works. Did my superduty fall victim.

 

The lock mode on auto hubs is to be used if the vacuum system fails and the auto hubs won't engage automatically

 

so you shouldn't use them unless the auto fails? i would think a mechanical device is more reliable than an electronic one...

 

you are supposed to leave them in AUTO and only turn them to LOCK if the vacuum system fails

 

Actually, I think schmidt64's understanding is a bit off - it was also my understanding until I found this site a while back, and I think it is the understanding of most of the people with ESOF in their Ford trucks. Unfortunately, the manual that comes with these trucks is not very good at explaining this 4x4 system.

In fact, the manual locking feature of these hubs can be used when the vac system fails (as noted by schmidt64) but can also be used if you are already stuck and still in 2-wheel. For example, if you drive into snow, ice, sand, mud or similar and get stuck, you CANNOT lock the front hubs with the ESOF while stuck b/c the system requires about 10-20 feet of movement to engage. In this case, you must climb out in the muck and lock them yourself - you can still engage the transfer case and front drive shaft via the dash switch.

However, the other strong recommendation by those on this site whom are much more knowledgable than am I, is that you manually lock the hubs once per month to prevent them from "freezing" in the auto position and also to lubricate the front axle. For this purpose, DO NOT engage the transfer case and front driveshaft via the dash switch while on dry pavement. Having the front hubs locked will not harm anything, but engaging the transfer case while the hubs are locked on dry pavement will likely cause your transfer case to implode and that would be bad.

So, use the ESOF when 4x4 is needed and you are driving. Use the manual lock on the hubs when you are already stuck, and also once per month to keep them moving freely and to lubricate the front axle and seals.

Hope this helps.

 

I've always manually locked if i knew in advance the situation called for it. Examples would be running the truck at the sand dunes or a two or three day snow storm during the winter. The only downside is slightly increased gas mileage due to higher driveline drag, there will be no damage to the hubs at all. AUTO hubs are for people that don't like the hassle of "locking up" and also to compete with GM & Dodge who don't even have hubs but use the center axle disconnect system. There is no manual over ride on their C.A.D. system when it craps out.
As far as engaging on dry pavement, amend that to "do not engage on dry pavement UNLESS MOVING OR IN NEUTRAL". When you're moving the gears will mesh when the shift fork starts moving. If you're parked with locked hubs frequently the gears will bind until the driveline "twitches". That's why you can only engage Low Range when in neutral, not in Park. Neutral allows for the driveline to "twitch" and ensure complete engagement and lighting the dash indicator.

 

Good explanation as to why movement (or neutral twitch) is needed to engage the hubs. My warnings on not engaging the 4x4 system on dry pavement was in regards to tight turns and tracking - which would have negative results for the transfer case.

 

That "clunking" you are hearing is probably the u joints on the front axles binding up when you turn too sharp. When you maually lock your hubs in, without engaging 4 Wheel Drive on your transfer case, it still rotates your axles through your front differential. When you turn to full lock either way the angle on the driveshaft u-joints is too great and causes them to bind while they are trying to spin. This doesn't happen when the hubs are unlocked because the axles won't spin.

 

I flip the hubs from auto to lock at least once a month to keep them loose. My brother does it with his '95 after having a problem with a hub and has not had any trouble since. I also drive in 4X4 once a moth to keep everything lubed.

I really like ESOF since I'm lazy! We'll see how it holds up with the PM discribed above.

 

Esof will engage when your stuck you do not need to move the truck for them to engage as the axles will turn and lock in the hubs. I played with this on mine and I know it works.

 

I believe that the Auto-Locking hubs of the F250 are being confused with the Auto-Locking Hubs of the F150. The Auto-Locking hubs of the F150 are famous for failing and work entirely different than the ones used on the F250.

The F150 hubs are engaged when the transfer case is engaged and the turning motion of the front axles and this is the only way to engage them, there is no visible indication that the front hubs are engaged.

The F250 hubs are different, when the transfer case is engaged, the hubs are engaged by the turning motion of the vacuum operated servos in the wheel hubs and ther is a visable indication that the hub is engaged. Have someone operate the switch, while you ae outside and looking at the wheel hubs, you can see the locking hub moving to the "Lock" position.

Also when engaging the 4x4 also engage the low range as well, the truck must be stopped and the transmission in neutral for the transfer case to shift into low range.

 

now THAT is cool!


i was tryin to figure this out last night. i put my new one in 4 for the first time, and it refused to make a turn...it was hoppin around and pushin me out of the turn. it was on dry pavement so maybe that was the problem? it wasn't even that sharp of a turn, just a 90' turn at a stop sign kind of thing. i took it out of 4, went down the road a bit, tried it again and it was fine. any ideas what i did wrong?

 

Ah yeah....not exactly. The dial only moves when somebody turns it. The auto function operates off a vacuum pulse. There is no visable indication that the hubs are locked up when they are in "Auto".

 

I believe you are a little confused on this one.

The 150's use a center disconnect sytem. It has CV shafts to the wheels and those are ALWAYS engaged. That is one of the reasons that you don't wnat to run a locker in IFS trucks, your steering would ALWAYS be tough.

The 4wd system on the F250 auto hubs are vacuum actuated. The only servo is the one that engages the transfer case. When you activate the 4WD, this activate the t-case motor and vacuum is applied to the hubs. There are no servos in the hubs.

Also, the hubs DO NOT rotate to the "LOCK" position. This is for manual operation if the vacuum system fails, such as a broekn vac line or a leak in the system somewhere. It does not do this when you use AUTO, it stays in the auto postion.

Now, as to needing movement to engage, this is not correct. The 250 hubs only need a slight nudge to engage the splines in the hubs. This is just to get them to seat fully. This will happen as soon as you activate 4wd and put it in drive if you are stuck. That's all the movement it needs.

The only VISIBLE indication you would get is the u-joints turning when power is applied.

 

Your truck behaved exactly as it should in 4WD on dry pavement. In 4WD on an F250, there is no differentiation between the front and rear axles, so when the outer front wheel tries to rotate around more than any other wheel on the truck (as you go around a corner) the other wheels (locked to this front wheel thru the drivetrain) won't let it. Hence the hopping and chirping of tires. Obviously, this is why 4WD should be used on loose surfaces or for short distances in a straight line (such as pulling a boat out of the water).


Steve

>>>>>
i was tryin to figure this out last night. i put my new one in 4 for the first time, and it refused to make a turn...it was hoppin around and pushin me out of the turn. it was on dry pavement so maybe that was the problem? it wasn't even that sharp of a turn, just a 90' turn at a stop sign kind of thing. i took it out of 4, went down the road a bit, tried it again and it was fine. any ideas what i did wrong?