OK some weeks back I posted needing help with my rebuild/greasing of my 4wd hubs. Cause: 4wd didnt work one day. Well I know it works now,no questions about that now. Truck: 2003 f250xlt 7.3l 4x4

Here is my questions:Which way do I turn the OEM ESOF switch to make 4wd engauge? Please advise..... my ignornace is killing me


I was under the impression that no matter what position the selector was in, if I hit the in cab switch the 4wd would engauge....??? That is not my case.

Also by the owners manuals pic it looks like to me it says to 'lock' you turn both towards the cab. Again I do not know. I did this the other day, no 4wd.
"Turn them both to the right" a guy at work says so I do and 4wd works.

Again this is the 1st 4wd truck I have owned. I have had 4wd company trucks that were chevy's, 4wd in the floor. I have searched and read so much but still am confused so please forgive me on that
THanks

 

If you turn the indash selector it should engage the hubs no matter what the hub selector is in. If it only works in one position then you probably have a vacuum issue. Check the vacuum hoses around the back of the wheel first for cracking and check that your vacuum pump is cyclying. You may also have a bad o-ring in the back of your hub. If you have a mightyvac you could test for that also.

 

The hubs are marked AUTO and LOCK. AUTO will allow them to engage and disengage by the switch on the dash. If that fails then you can manually put them on LOCK. However, this means they are locked regardless of what the dash switch says. Just remember though, when in LOCK, only the hubs are locked. The Transfer case wont connect to the front drive shaft until the the switch is in 4lo or 4hi.
In the auto position, when you flip the switch to 4x4, it uses vacuum to engage the hubs and also engages the transfer case. But as CPS already said...if there is a vacuum leak, the hubs wont work.

One way to test is to turn on your heater, make sure the air is blowing out the bottom vents, then turn the switch to 4x4. Then wait a few seconds. If the air changes on its own to the defrost vents, you have a vacuum leak. It could be a hose, or the o-ring around the hub. Both are pretty easy to fix. Just some basic hand tools.

If you do a search for HUB LOCK on this forum you will find all sorts of info on them as well as someone prolly posted a link to the instructions on rebuilding the hubs and replacing the o-ring. As for the hoses..well that is on you to check them all the way back from the hub to where ever they connect to. Just need to be sure there are no cracks or breaks.

If you cant see the labels on your hubs to know which is AUTO and which is LOCK, I can check mine and post which way to turn them for which option.

 

THANKS for the replies so far. I think I get it now. This is just a bit confusing. As for the o'rings behind the hub, about three or four weeks ago I had the complete hub assembly off to do the hub service and to grease the hub assemblies. I had the new o rings on hand and did replace the yellow and the black ones when I put it back together. I will try the heater test and see if it goes to defroster. I bet I have a vacuum leak in the engine side as when I did the service I replaced the lines to the hub where the brake line goes.

Thanks again

 

I don't have my owners manual but I'm pretty sure the esof switch only auto engages the front hubs in 4wd high. To lock in 4wd low you put the trans in neutral or park, esof switch to low then you manually lock the hubs. If you just switch to low, it doesnt engage the front hubs, just the transfer case goes to the low ranges. Correct if i'm wrong. thnks.

 

For lock.......the hubs both turn clockwise.

For Auto lock......the hubs both turn counter-clockwise

This is on my '00 F250.

Even with one in lock and one in auto lock, you should get 4 wheel drive once you select it inside the cab if all is working correct.

How are you testing for having 4 wheel drive locked in?

Low range works with the hubs being in either auto or lock.....according to the owners manual.

 

You are right about the 4Low process. You must be stopped and in neutral.

But in general...the switch does engage the hubs (if working) and t-case either in 4hi or 4lo. At least mine does.

 

OK so I thought I had tested with the defroster before. Just did it again and indeed it does switch itself over to defrost with the heater on floor mode. Should it continue to blow through defrost as long as 4wd is selected? It does only go to defrost mode only for around 30 seconds then no more defrost all is returned to the floor.. Now to get the mighty vac out to start testing.

As for the test method in 4x4 was in a horse pasture and really needed 4wd but when hit the in cab button, nothing. Lock in hubs 4wd is good low range included. SARDiverDan sent me some OEM hubs a few weeks back and I used one. I did need a passenger side one as it had bad bearing and some plastic chewed.
Thanks again

 

It depends on how bad the leaks is. if really bad, it wont go back to floor heat. Sounds like you have a crack in a line somewhere. once it loses enough pressure the cracks closes enough to build some up again.

 

I think it could be in the new hose I put on from hub. It seemed to be a bit loose when I installed it. I almost bet that it is at that point and when it gets the vacuum really applied to it it seals itself off. I do own a mighty vac and will have to dig deeper this weekend, maybe. Now atleast I do know that to lock they both need to go clockwise and vise versa. Thanks for the quick and easy replies. Made my day