I have a 97 f150 scab with the 5.4 and today I was on a few trails and the 4x4 was working fine, and then I stopped and put it in 2wd for a minute, and put it back in 4wd again but it stopped working after that and it didnt work the rest of the day. When I got home and started looking at it I found a plug by the front differential that looks like it came undone, but I can't find where it went. Could this have something to do with the 4x4 not working? I also tried putting it in 4x4 again tonight and when I went into 4x4 low you can here it click like it is engaging, but it doesn't do this when you go into 4x4 high. But neither of them worked today. Also, when I am on the road if I have it in 4x4 you can feel a small difference from 2wd, but in any mud today the front tires would not turn at all. Does anybody have any ideas about what could be the problem?
Thanks for any info

 

It's probably the shift fork inside the front diff is broken , I bought my truck used that way , almost got stuck the first time 4x4. It's like 250$ for the kit from the dealer and pretty easy to fix.

 

Ok, how did you find out that it was the shift fork? Did you take it to a dealer or can I find out myself?
Thanks

 

ok here is a picture of the plug I was talking about in my first post. I can not find where this plugs in at but I think it could have something to do with my problem.

 

Ok well that picture didn't work but I think this one should. Also, that is the left fron axle if that helps any. I also posted an album on here with a few more pictures.

 

There is a small vacuum operated lever by your front differential that engages and disengage your front diff. Make sure that is not the vacuum line that attaches to it.

 

Ok, I looked under it again and everywhere by that lever and I can't find anywhere where that plug could go, but their isn't one connected to any part of that lever that comes off of the diff so that could be it, but I just can't find the plug. Also, if I follow the line up a little more it splits, and there is another plug like it that is plugged in, and the rest of the line goes up towards the engine. Does anyone know where I could find a diagram of all the wires for this?
Thanks

 

Well today i zip tied the shift lever so that it was locked in position and he 4x4 worked so I am guessing that plug has something to do with one of the vacuum lines. I know if I get a posi-lok kit it will eliminate the need for the vacuum system so I am thinking about doing this, or possibly trying to make my own since it doesn't seem that difficult and this seems like a pretty common problem on these trucks.

 

lol, that plug is for VSS which you do not have.... its a steering assist that none of our trucks have... everyone has that plug hanging n wanging

 

Why would they put an extra plug on the truck for something that's not there? I found the posi-lok kit for $100 brand new and just got it today. I know this will fix it and I don't really want to deal ith the vacuum system becase it pretty confusing to me,and it seems like a pretty common problemo this should be much more reliable and hopefully I won't have to worry about it after this.

 

It's so they can use one wiring harness for the most number of different vehicles.