Spent a few days reading, diagnosing, eliminating problems.. but still got some weird issues I need some guidance chasing down. Being winter in Montana, no 4wd gets to be a bit of an issue, time to get this sorted out.

PROBLEM: ESOF not going into 4wd at all, exept once in a blue moon... for a few times.

all relays and fuses tested, swapped with known good units.

NO 4x4 light. so its electrical related. My hubs function like they should. when they are told to. I recently just swapped esof motor/gearbox on the TC. worked 2x in the garage, went for a spin down the road, went into 2wd and stayed, wouldnt go back into 4hi brought it back inside, dinked around with resetting the GEM fuse. started working good. drove around and switched in and out of 4wd like 20 times no issues. next day, tried to go back into 4wd. nothing. Bring it back in the garage.

CURRENT DIAGNOSIS: Siting inside right now, If I flip the switch, I don't get anything. normally, that triggers the vaccum pump to suck hubs in. that doesnt turn on, the relays under the hood dont click. so it seems I am back up to the switch or GEM, or wires between....

Does anyone have a test layout for how to test the switch in the dash? seems to be fairly simple, but I just wanted an exact view of what i need to test. and any thoughts you guys might have.

Thanks,
Nick

 

It helps a lot if you actually specifically identify your truck....

 

HAHA, yes, a little to only asking people who know what I have for help.

2000 F250 7.3 6spd... man i love this truck, but wishing i had manual 4x4 right now.

 

hmmm... took switch apart. tried to check each resistor and getting OL across all of them. i cant imagine all of them burning out... but who knows. gonna grab some new ones here and solder them on as a quick test. no reference voltage to the GEM could cause me some trouble.

 

This might help. Third post shows the wiring diagram for the early ESOF systems.

https://www.ford-trucks.com/forums/9...of-help-2.html

Since we don't know what truck you have, so be careful of the application. There was a change, requiring a new GEM be dealer "flashed" in 2002-03.

 

Did you have the ohmmeter set on a proper range (20K)? Does the meter read '0" when the probe tips are shorted together? Did you try the resistance readings from the connector terminal pins 2 & 3?

 

yes on range, i tested and developed electronic stuff for over a year recently as as job, so im no EE, but i can run a multi no problem.

threw a new switch in, nothing still. tested the new switch for fun, same readings, grabbed a different multi meter... now i get readings. apparently mine took a dump along the way. glad that thing just sent me chasing down one of the wrong roads.

so now I am up to new TC motor and new switch. still getting nothing happening when the switch is getting flipped. No vaccum pump and hubs working, nothing, so it would seem to me I have troubles between my switch and gem area. yehaw. time to tear the dash apart and start examining wires.

 

I had this problem in my 94 Ranger. The ultimate fix was switching to a mechanical T-case. However, I was able to remedy the problem a few times. Changing t-case fluid to synthetic helped mine because the high quality fluid reduced the friction needed to switch into 4x4. I also had luck with removing the shift motor from the t-case, disassembling it, cleaning it with electronics cleaner, greasing the bushings with a good synthetic grease, and reassembling. This help for a while, but I was unhappy with the complexity of a system I needed to work reliably. In my case, it was cheaper to get the t-case I wanted from the U-Pull-It junk yard than it was to replace the shift motor. That was route I took and was even able to sell the old case and get half my money back. If you use the truck off road or need 4x4 regularly, I would suggest spending the time and effort to make it what you want.

You would need a NV271 w/ wiring harness, shifter assembly, cab adapter plate, and some time. They are relatively simple swaps and in the case of the Ranger, I was even able to get the dash lights to work. Two of the wires going to the shift motor harness are the limit switches to the dash lights. When you ground them, the indicators on the dashboard come on. All you need to do is splice them with harness on the new case and the should work.

Someone else may be able to add the experience of doing this on a SD instead of a Ranger, but in principle, it should be the same. I have a buddy with a 2000 F350 7.3 6 Speed Dually who did this swap with no problems.

Hope this helps and good luck!

It would be beneficial to have a good set of manual hubs too. No need for autos with a lever

 

already got a new shift motor, no power from upstream.

I do like manul4x4/manual hubs but i will admit, this setup works good for my application, I live in MT and all winter i start at my house and the shortest way to work is through a non plowed road between fields (need 4x4) then onto dry pavement into town where having hubs locked in sucks trying to drive around and park or do anything. the esof/auto combo makes it so i can actually use my truck in town and not feel like im raping the front end but still throw it in 4x4 to make my way to and from work.

Hunting for a GEM off ebay... thats about all i got planned to do next.

 

I have ESOF, but have manual front hubs and I don't have any problems leaving my hubs locked in. I might hear a little noise in really sharp turns, but that is it. Does your truck have a front locker or something installed?

 

this is really irrelivant honestly. the vaccum hub system works fine, if i care to, i get out and lock them in manually for peice of mind if going into a nasty spot. Doesnt matter if the hubs are locked in if the t-case is hanging in 2wd.