2001 F350 esof 4x4 issues.

[sethc24]

Okay guys. When the truck has the esof system. When you turn the dash knob to 4x4 hi the 4x4 light comes on and you can hear the electronic motor on the transfer case engaging and disengaging. But the 4x4 is not working so i am assuming something related to hub/ vacuum solenoid. I found the vacuum hose on the passenger side in wheel well had a split in it. So i replaced it. still not go.Any ideas?


How do i go about testing the vacuum solenoid in the engine bay?

 

[sethc24]

Okay i took a vacuum reading at the hose coming from the PVH solenoid. With 4x4 switch and key on. I got a reading of 15 in-hg of vacuum and then after about 10 seconds it goes back down to 0. I took the reading the hose that connects to the hub and got the same reading again. So i'm thinking problem is with the hub assembly o-ring inside etc? any ideas on this?

 

[JLDickmon]

if you can't pump it down with a hand pump, sure.

sounds good to me..

 

[sethc24]

Pump what down by hand?

 

[G Racing]

The oring could be worn or you could have gotten water in the hub. If you you turn your hub to lock your 4x4 should work. Your auto just won't.

 

[JLDickmon]

Pump what down by hand?

If you put a hand vacuum pump on the fitting on the knuckle, and can't draw it into a vacuum, you know where the problem is..

 

[sethc24]

ah i see. The hubs are almost impossible to turn by hand.

 

[JLDickmon]

ah i see. The hubs are almost impossible to turn by hand.

I'd think that is a problem itself..

 

[Racer X]

ah i see. The hubs are almost impossible to turn by hand.

I'd think that is a problem itself..

Yes. :thumbup:

 

[TyCorr]

ah i see. The hubs are almost impossible to turn by hand.

First off, pull the snap ring on the locking hub and pull the assembly off. If its bone dry or rusty in there you need to figure out where its leaking. Rebuild as necessary. You can fashion a tool out of pipe or even pvc pipe to turn the hubs.dial by cutting a.notch in the.pipe to grab the dial on the hub. Sometimes the oring just dries out behind the locking hub itself.

 

[sethc24]

found a solution. Warn locking hubs.

 

[Racer X]

found a solution. Warn locking hubs.

That's one proven and time tested solution.

We stock Warn winches and locking hubs in standard and premium versions.

 

[TyCorr]

found a solution. Warn locking hubs.

Thats what I did. Screw those ford POS. Unless you are running 33's or less, the esof hubs arent gonna cut it.

 

[TreeMos20]

01 350 ESOF problems

Ok. 2001, F350, 7.3 diesel, Lariat. Noticed my ESOF 4x4 was not working, no light on dash, nothing. Then noticed my vents would only work on defrost. So did some research and ended up replacing the Hub lock actuator that connects to the vacuum pump, kinda forward of the actually vacuum pump. Still no 4x4 but the vents were working on all moods. then crawled under and found the plug connected to the front of the transfer case was loose, pushed it on tighter. turned key to aux and 4x4 only seemed to work on HI but then truck would not start just kept rolling over but would start and vacuum pump never turned off. crawled under and undid the plug on the transfer case, truck started fine, let run for awhile, then shut it off, put plug back on, truck started fine 4x4 (HI only) seemed to work but now the vents would only do defrost. Any ideas? can't seem to get 4x4 hi and low and vents to work. either a bad hub, which buy the way are manual and only go from lock to free, bad vacuum line, bad ESOF, or just bad connection at transfer case?? And what could be wrong with 4x4 low? Thanks for all the help in advance

 

[TARM]

Your pump is working like it should. Those reading and the stop etc is all normal. The pump does not put a constant vacuum it pulls vacuum to lock and then stops. It then will pull vacuum again to unlock. Think of a push button writing pen click once to extend point click again to retract. Same deal
'
The issue and you found it is your hubs have seized up. You may be able to salvage them. Go to Guzzles page and it shows how to break them down and put them back together etc.. Also there is new gaskets you should install that you can order from him as well.

Pick up some silicon and break free sprays etc. You need to get that knob turning. Cut a slot in a end of a piece of sch 30 pvc. Enough so the part you turn can fit in it. Add a 90 T to the end of it so you can turn it. Place it on there and you should after some soaking and spraying of lube around the edges so the lube gets in there get it to turn. You will need to just keep turning it back and forth until it gets easier and easier. Once its easy enough to turn by hand put it all back together and install it. Make sure everytime you fill up you give them a turn to keep them from freezing up again.

the other option is to purchase some warn premiums and call it a day but they will be manual only. No more stay in the cab and have 4x4 at only the push of a button.

 

[Racer X]

Ok. 2001, F350, 7.3 diesel, Lariat. Noticed my ESOF 4x4 was not working, no light on dash, nothing. Then noticed my vents would only work on defrost. So did some research and ended up replacing the Hub lock actuator that connects to the vacuum pump, kinda forward of the actually vacuum pump. Still no 4x4 but the vents were working on all moods. then crawled under and found the plug connected to the front of the transfer case was loose, pushed it on tighter. turned key to aux and 4x4 only seemed to work on HI but then truck would not start just kept rolling over but would start and vacuum pump never turned off. crawled under and undid the plug on the transfer case, truck started fine, let run for awhile, then shut it off, put plug back on, truck started fine 4x4 (HI only) seemed to work but now the vents would only do defrost. Any ideas? can't seem to get 4x4 hi and low and vents to work. either a bad hub, which buy the way are manual and only go from lock to free, bad vacuum line, bad ESOF, or just bad connection at transfer case?? And what could be wrong with 4x4 low? Thanks for all the help in advance

Hmm, just some guesses at what's bad based on some of the symptoms you're describing. Vacuum pump wouldn't shut off - leak somewhere or check valve/release actuator sticking open. Vents only work on defrost - possible no vacuum or low vacuum signal reaching heater controls. By design, some vents work only in defrost mode w/o vacuum as a safety feature. This way the windshield can still be defogged/defrosted for clear visibility in all driving conditions when there isn't enough vacuum to run all controls/accessories.
The conversion to manual locking hubs has always been the time tested solution. The first auto hubs came out in 1994 and either wouldn't engage at all, wouldn't stay engaged or didn't hold up very long in use. The driver usually found out after they were already stuck -:cursing: and needed a working 4 wheel drive. Those first auto locking hubs were pulled from production eventually, replacements and repair parts went obsolete very quickly afterward. That system was just to avoid getting out to lock hubs, no shift on the fly.
If you're determined to keep the factory vacuum hubs/shift on the fly, an EVTM would be a valuable resource to buy for trouble shooting.
We and most shops would charge by actual time in hours to repair these. Plus there is no longevity guarantee or repair warranty for how long they will work if parts of the system are obsolete from the OEM's. There maybe whatever warranty a guy like Guzzle would offer on the gaskets etc. he sells, should they leak within a certain time period. If offered, that's on the parts only. So it goes whenever any components or system on anything becomes obsolete, was trouble prone when new or is impractical to fix as it was made. Then it's either bear the cost and risk of repair or go with the aftermarket solution that works best to solve the problem long term. Good Luck - :toast: :thumbup: