Sorry about the confusion. I was writing my response about an F250 not an F-150. Manual hub locks on the 250s need to be turned by hand. So you need to plan ahead by engaging them before you are up to the axles in shìt.

JMC

 

The original question was asked with regards to an F-250 AKA a Super-Duty. Last I saw, teh SD had two hub options with the manual case: auto hubs or manual hubs. With the ESOF, you got the auto-lockers. The autos are notorious for binding up and failing to release. I can't vouch for the manuals, but I can say that a set of aftermarket Warn manuals can and do cause front axle breakage.

As for the manual versus automatic, it just depends on your preference. Both systems rely on the electronic controls to engage and disengage the front axle, so pick your poison.

-Joe

 

My mistake too. I am so used to this being F150 Online, I forget to look for the other models.

 

ESOF (Electronic Shift On the Fly). Means you can go from 2wd hi to 4wd hi or vise-versa while moving (or on the fly). You must put your truck in Neutral to shift into 4wd low (since it involves a different gear in the transfer case).

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When you turn your dash ****/switch from 2wd hi to 4wd, several things happen:

The motor on the transfer case 'basically' connects the front drive shaft to the transmission. Thus, now the front drive shaft turns in unison with the rear drive shaft. And now the front axle turns with the front drive shaft. So far, the front wheels are not being driven by the front axle - not yet anyways.

Sensors at the transfer case 'basically' sends a signal to your 4X4 & LOW RANGE lights on your dash board. Now this is where it can get confusing - the dash lights do not indicate whether the front hubs are locked or not. So you could have a 4x4 dash light on but your truck is still in 4x2 (transfer case motor working but front hubs are not). Or you could have a 4x4 dash light off but your front hubs are still locked (transfer case motor working). Or you could have a 4x4 dash light off but you are still in 4x4 (light bulb burnt out). As you can see, you cant always trust the dash lights. Unlike the new auto/lock hubs - when you have problems with the transfer case motor not working, you are not going to be able to override it to put it into 4x4 (this is probably the biggest gripe people have about the ESOF system).

The front hubs 'basically' connects the front axle to your front wheels. This system uses timed vacuum sequences to lock and unlock the wheel ends. A high vacuum level is used to engage the hub locks, and a lower vacuum level is used to disengage the hub locks, after which the vacuum is released and the hub lock holds itself in the proper mode. The vacuum signals are supplied to the hub locks by system components, including Generic Electronic Module (GEM), wiring harness, solenoid, vacuum harness, and vacuum seals. Some 'noises' (suck as a click/clunk/thud etc.) during hub engagement/disengagement is normal. As a first step in service, eliminate such obvious items as loose wiring connections, loose vacuum connections, or damaged vacuum lines. On newer auto locking hub systems, you can override them by turning the selector to manual when you have problems with the auto lock feature.

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WHY ESOF FAILS - The biggest problem people have from ESOF systems (believe it or not) is under-use. They only use the system 1-2 times a year when it is slick outside. Then it will go several months without being used. Do yourself a big favor, at lease 1 time a month (even on dry pavement) - on a slow short straight away area - engage and then a few seconds later disengage the system. Do not go very far or turn on dry pavement with truck in 4x4 or binding of the drive train could occur. Also, every now and then, rotate your AUTO/LOCK hub selector back and fourth to keep it moving freely.

MANUAL OVERRIDE - The newer AUTO/LOCK hub locks have manual override selector dials which makes them (at a quick glance) look the same as the non-ESOF hubs with the LOCK/UNLOCK selector. When rotated to the "lock" position it will keep the mechanism locked regardless of the instrument panel 4X4 mode switch position. For the most part, keep them on the "auto" position.

The older auto hub locks do not have any kind of manual override selector dial.

HUB DISENGAGE TIME - "Slow" release of the hub locks is not considered abnormal for this system according to Ford TSB (Technical Service Bullitins). Anytime vacuum is applied to the hubs, whether for 4X4 or 4X2, the hub locks will initially engage. If 4X4 was requested, they will remain engaged, but if 4X2 was selected, the internal mechanism will release only after the GEM timers expire and vacuum is vented from the hub. This normally takes 15 seconds, but can take up to a whoping 2 minutes depending on how the 4X4 mode switch was operated. After the hub mechanism releases, internal springs must work the hub lock gears to the disengaged position. Road bumps, vehicle speed, acceleration cycles, or momentary reversal of direction can assist this process, varying the length of time the hub locks remain engaged in each situation.

MATCHING HUB PAIRS NOT REQUIRED - Left and right side hub locks are not connected other than by the common vacuum supply line. If a malfunction in either hub lock is diagnosed, it should be replaced as an individual unit; there is no need to "balance" an axle with new hub locks on both sides. If both sides appear to be malfunctioning, be sure to verify upstream system integrity before replacing both hub locks.

 

HUB LOCK REMOVAL - After removing the hub lock retaining ring, be sure not to use tools other than hands or "grip" gloves as damage may occur to either the paint or function of the hub lock. Pliers or channel locks should be only considered as a last resort as they will usually damage the hub lock, making replacement necessary.

HUB CONTAMINATION - If contamination (water, mud, etc.) is found in the hub cavity, look for the source. If it is due to system leaks other than the hub lock, they must be found and repaired. Always replace the hub lock O-ring before re-use.

TORSIONAL FAILURE - If a torsional failure (twisting fracture) of the hub lock is suspected or the internal gears are "shattered", the axle constant shaft may have been damaged as well. Inspect the axle shaft carefully; if twisting has occurred at the base of the axle splines, it is difficult to see without removing the bearing assembly.

RATCHETING - If a "ratcheting" noise is found especially over road bumps and potholes, suspect the needle bearing that supports the inboard end of the axle constant shaft within the hub/bearing assembly. Eliminate this as a cause before servicing the hub lock. Wear at this bearing can set up vibration, which may be heard as ratcheting, while a seized bearing can bind the shaft, forcing it to rotate in 4X2.

 

One 4x4 system is not "stronger" then the other per say. Both will pull stumps just fine. Both have the same 4x4 HI gear ratio of 1:1 and the same 4x4 LOW gear ratio of 2.72:1.

If you are pulling on something with the ESOF system in 4x4 LOW and if for some reason the auto front hubs hesitate to engage (which is normal) until your rear wheels starts to spin - then you can have some problems (see my 'TORSIONAL FAILURE' under the title "The Basics of ESOF II" above). So, before pulling on something in 4x4 LOW - make sure front hubs are totally engaged (you can do this by means of moving manual override selector dial from AUTO to LOCK).

Another example of TORSIONAL FAILURE is when someone in an ESOF 4x4 system gets stuck while in 4x2 and not even thinking about it - while still spinning out the rear wheels - switches to 4x4 HI. Kinda like doing a neutral drop. You will hear the front hubs shatter. Spinning out in the ditch or on ice, it is very easy to be doing 30+ mph. The damage is done, your truck is unable to go into 4x4, and you are still stuck. Time to call for a wrecker to winch you out.

The ESOF system does have more chances of something going wrong with it in the long run - even though it has improved a lot in reliability throught the years. Ford does charge another $185 to add the ESOF feature (from the factory). If there are any problems, the repair costs are a lot more then 'manual' systems. Most serious 4-wheelers/off roaders dont like ESOF.

'Manual' (the floor stick) saves you $185 and is more reliable then ESOF in the long run. Less chances of problems down the road. If there is any problems, the repair costs are a lot less then ESOF systems.

 

Good data!! Everyone, please note: the information posted above applies to the Super-Duties and Super-Duties only. The F-150s are a completely different monster.

-Joe