I just recently sold my 1992 F250, which had manual locking hubs, i had to get out and turn both front hubs to get the truck in four wheel drive.

My new truck is a 2001 that has "shift on the fly" but it still has the parts on the hubs that I twist. The dealer told me this was for "extream" four wheeling, sssuuurrreee. Is it for posi? or do I not have shift on the fly??

Also which direction is on or off for whatever they do. The only thing on the part of the hub that rotates is a little indent, so i guess either right or left of that indent is on or off. Thanks.

 

Welcome to the site!

I don't have one, but from what I remember looking at them is. There are two possitions on the hub. 1 is Auto, and you can roll on the road all day, and then while in the cab shift into 4wd and now you have 4wd(auto). 2 is lock(if I remember right), and I don't see the point to this other than it just leaves the hubs locked in all the time(so it elimates all the extra parts that can easily break while in auto....I think). But the lock does not give you limited slip. The axle would have to have a limited slip in it for that to work...The hubs can't do that.

I'm sure someone will come along to clear this up...

 

Thanks but I still would like to know which position is locked and visa versa, is it bad to drive with them locked? probably but i dont know what is locked and what is not! sucks, if someone knows please help. thanks. I am also going to contact ford directly when i get a chance so when I know i'll write back.

 

The ESOF system is known to be troublesom. It works on a pulse vacuum system that automatically locks the hubs while in the auto mode (dial turned all the way counter clockwise). There is a possibility that the hub may never lock if the truck is stuck and the wheel, or axle does not spin enough to actually engage the hub. Poor vacuum lines and actuator commonly fail, and prevent the hub from locking, or just as bad, unlocking.
The manual setting (dial turned all the way clockwise) eliminates the possibility of the hub not engaging, sine the thing is now manually engaged. This does not mean that it will disengage though. It still requires a vacuum pulse to disengage. I see Super Duties driving around on the street with the front driveshaft spinning all of the time.
I always suggest to SD owners that they verify the free movement of the axle by spinning the axle at the knuckle after dis-engaging 4wd.
The failsafe option would be to eliminate the auto / manual hubs and install a quality set of aftermarket units. Can't beat the manual hubs for perfect performance every time. When they are locked, they are locked, and the same is true for the opposite.
MBBFord is correct when he states that this has no effect on the differential, it only determines whether or not the front wheels become engaged.

 

75F350 is correct the ESOF on the super duties are very common to fail, usually the vaccum lines, the hub, since it's an 01 it used a mechacnical diode on the transfer case which is very common to go out. 99-00 it was an electrical diode, 01 the went mechanical found out it sucked and went back to electrical in 02-03. As far as your current hubs there should be lettering some where that says auto, and lock. you can run in lock all the time and it won't hurt anything unless you switch it to 4wd. I would suggest at the first signs of troulbe switch to Warn manual hubs. But there are a few people that never have problems with ESOF. Welcome to the site and good luck. You may also want to post this in the Super Duty forum they may be able to give you more answers. The transfer case motor for the ESOF is also a common failure. Sorry for all the bad news.

 

My 2001 has manual shifter on the floor and manual hubs. So I have a solid link between my shifter and the transfer case to engage it and my hubs are not vaccum but mechanically operated and have two positions, lock and unlocked.

If you have ESOF electrionic shift on the fly then you have a **** on the dash that when turned activates an electric device on the transfer case to engage it (that can go bad and keep yourself from getting 4x4) and you have vaccum activated hubs that have two positions, auto and locked. In auto they are supposed to turn free and not be locked in until you turn the switch on the dash board, while it activates the transfer case it also tells the vacuum pressure to change in the front hubs and makes them lock in (yes you have a vacuum hose running to each of your front hubs). When you turn the knod on the dash back to 2x4 it unlocks the hubs by changing the vacuum pressure and disengages the transfer case. If the vacuum seal is broken in the hub and you can't get them to lock in, then you can turn the hub dail to lock and it will force the hub to lock in. But it will never unlock unless it has a good vacuum seal. The auto hubs are designed to fail into the locked position. That is OK except you are turning the weight of the front axles and lowering your gas milage and wearing out all the moving parts down there when you don't need to.

If you reach in and try to turn your front axles with your hand, they should turn if you are in auto hub and the dash is on 2x4. If you leave them on auto and turn the dash to 4x4 (with the engine running to make vacuum pressure) then the front axles should lock and you can't turn them by hand. If they are locked in while the hubs are set on auto and the dash is in 4x2 then you have a vacuum leak in the hub and you are always locked in. If that is the case I would buy some warn manual hubs and close off those damn vacuum hoses to your hubs.

Hope this is helpfull info!?

 

this is extreamly helpful!!! thank you. I dont use 4x4 much and i love the auto so i dont have to get out of my truck and lock my hubs if i'm stuck. I am going to make sure that my axels turn freely and everytime i use four wheel drive i will check later to make sure im back in 2x4. Thanks again!

 

Actually manual hubs aren't so bad, If I think I'm going to need 4wd on the trip I lock them in before I leave, this way I can possibably avoid getting stuck to begin with. Then when I need 4wd I just pull back on the shifter and I know 4wd is in, otherwise with auto's you could turn the *** to 4hi and still be in 2wd, if the hubs or vaccum system fail. Otherwise If I'm not going to use 4wd I turn the hubs to unlock.

 

That is exactally right.

I do that every time.
IF I know or even think I'm going to need 4wd, I stop before doing anything and lock the hubs.

 

^^^^^ X 10
Can't tell you how many SD's I have pulled out because the ESOF system did not work. Between the Pulse vacuum problems and the hub failures, there have been many SD owners stuck in some embarassing situations.
Both of my SD's and even the Excursion all have aftermarket manual locking hubs.
(Actually the 02 has a complete Dynatrac pro-rock 60, and the Excursion has the 60 that came out of it, with Dynatrac bearing conversion, and 35 spline outers.)
Anyway, one way shape or form, they all have manual locking hubs, don't get me started on unit bearings! LOL.

 

oh ok. well I have the esof so for now i'm happy with it. If the vaccum hose's fail maybe i will change over to manual locking hubs, untill then, thanks!