My 4WD wont engage. Any ideas?

 

Have you checked the vacuum lines?

 

Try using the search function? There are hundreds of threads on this

 

Do you have a selector switch or a shifter?

 

I have the selector switch. I can hear it clicking behind the dash, but it won't engage.

The truck has been sitting in the cold for several months.

What would get into the vacuum lines?

 

You really should do a search to at least find the easy stuff. Check for cracked, broken or vacuum lines that may be pulled off. Check the solenoids behind the battery, and check the vacuum motor under the truck on the differential. If those all check out then it could be the clutch fork inside the diff. Check these things first, they are all easy fixes except the fork. If that's the case pm me for help I just changed mine a few weeks ago ( really not that difficult once you know what you're doing) check to see how much you mechanic wants to fix it though cause it's kinda a pain. Some got it fixed for 300ish my ford dealer wanted 1k so I did it myself for 225

 

Thanks for the reply, but is there a way to check those components?

 

Visual and audible checks for vacuum lines. I've heard about using ether for the line check, spray ether on the line and if the engine revs it has a leak. I don't know if I would do that though. Solenoids, use a voltage tester.

 

may have to take the battery out to check the solenoids and vacuum lines.. two solenoids, one engages 4wd and the other takes it out. when you shift in and out put your finger on each and you should feel them activate. if you feel them activate then they are good so then move to the lines that also start behind the battery. cant remember what color the lines are.. pink for sure and maybe blue or something... someone will chime in with the correct colors but check to make sure they are all connected and are not cracked. then get under the vehicle and have someone switch into 4wd (while in park and wheels chocked obviously) and look to see if the vacuum motor moves back and forth. this is what engages the clutch fork in the front diff. if it does move then its more than likely its your clutch fork.. if it doesnt the vacuum motor may be broken. in this case jack the front wheels up, disconnect the vacuum lines, turn the truck on, turn on 4hi get under and engage it manually then spin the driver side wheel.. if the passenger wheel spins also then the fork is fine and the problem lies with the vacuum motor, if it doesnt move then its the clutch fork.. do this numerous times bc in my case the 4wd would work sometimes and sometimes it didnt.. is what happens is the clutch fork has plastic shoes that wear out or break off from shifting... someone chime in if i have forgotten something.............ill see if i can get some pics of the clutch fork kit.. sucks bc it comes with several things that make it pretty pricey (190-220) when is all you need is the 2 dollar aluminum fork. let me know what you find out bc if it is the fork there are some options you may have as far as getting it fabricated to make it stronger bc this WILL happen again only a matter of time

 

this is a better way of testing the solenoids i just didnt know how to do it at the time lol