Truck: early 99 F-250 diesel lariat
Hey guys, I am trying to troubleshoot my ESOF not working. Let me start out by explaining the issue. A month or so ago it worked fine, and I took the truck in to get a damaged transmission and transfer case fixed. The shop tried to screw me out of a lot of money thinking I'm just some kid, but I know a fair amount about what the problem was so I called them out on it and they basically said tough and refused to give the truck back. Got the police involved and they got in trouble for fraud, but took sledge hammers to the transmission and transfer case to get back at me I guess. So I took it to another shop to get a whole new transmission and transfer case. After all that, and also I removed the dash to replace a switch, the ESOF does not come on. The light for 4x4 comes on when starting the truck, so it works, it just does not come on when the switch is put on either high or low 4x4. The wheel hubs are also brand new and I tried in both free and lock and nothing. Any suggestions of what to check? I'm thinking either they forgot to plug something back in when they installed everything, or maybe I messed up the switch itself when I pulled the dash off. Thanks guys!

 

update:
I went and tried checking the fuses and they were all good. did notice however that the vacuum pump runs continuously. I tried toe trick where you have the ignition on but not the engine and switch from 2wd to 4hi and listen for the click and there was nothing. What could be the problem?
Also I noticed the plug going into the transfer case is now held in with zip ties. Im thinking that could be the problem but I cant get it to work when I wiggle the plug around either.

 

Wow... thats a tough break.

If you can find the wiring diagrams online, you can get a pinout for the plug and test it. You may just need to get a new plug from the junkyard and splice it in.

 

I went and cleaned the plug and tried again this morning and the 4x4 light came on and wouldnt go away even if i dropped it back into 2wd. It also did not feel like the 4x4 engaged.

 

Can you pull the motor off the transfercase and see if it rotates when you put it in 4x4 and so on?

You can also put the truck up on jack stands so all wheels are raised and actually try stuff out without fear of it going anywhere.

 

So update: the motor in the transfer case needed to be replaced, as well as the vacuum pump. The mechanic did that then test drove it around a bunch and said it worked fine. Now I have it back I can't get the 4x4 to work. They put on manual hubs too, so I switched them from free to lock, then turn the **** from 2wd to 4x4 high when driving and nothing. Switching into 4x4 low doesn't do anything as well. Am I doing something wrong? I called the mechanic and they want to see it again, and he also told me I'm not supposed to engage 4x4 unless the wheels are slipping. Is that true?

 

I would unlock the hubs and try to see if it shifts while sitting still. You need to have the truck in neutral with your foot on the brake to get it into 4-Lo.

When it comes to shifting on the fly, the only time I will engage 4x4 is if I am driving in a straight line with no wheel slip. Whenever you turn, the front and rear drives shafts are rotating at different speeds making the 4x4 engagement very rough. The same is true when one set of wheels are slipping and the other are not. Different rotation speeds make for a violent shift into 4x4. I am not sure if the electonics in the F250 limit you from engaging in these situations because of readings from the wheel speed sensors or not, I learned most of this on my Ranger. I've taken that knowledge and tried to be gentle on the F250 as the parts are much larger and much more expensive.

 

I agreewith this - I only shift into 4hi when I have the wheels straight and I'm coasting (foot off the accelerator). I think the max speed I've ever engaged it is around 30 mph.