I have a 2000 Ford F150, 4x4 the front wheels will not engage when placed in 4LO or 4Hi. I have replaced the actuator, both selonoids and the 4x4 shift motor. When I turn the switch on the dash to either 4Lo or 4Hi I can hear the transfer case kicking in but the front wheels do not turn. What could be wrong?
Yes I have checked the vac lines behind the battery box seems OK. Put a vac gauge on actuator and have vac there. Had my brother manually engage the actuator and the front wheels turned. How much of a job is it to remove the shift fork? Can I find anything on utube about removing and fixing the shift fork.

 

Moved to correct section.

 

Have you checked to make sure there's not a crack in the line

 

When you engage/disengage can you see the actuator move? If so, I'd bet the shift fork is broken.

 

x2 on the shift fork

Happened to me so I stole a version "A7X" sent to me then made my own with copper tabs like that

 

Bombs, I'm not sure if this applies to your model year (I suspect it does), but I came across this post elsewhere after I noticed my 4x4 light would not go out when it was supposed to and front diff would not disengage. Both happened in the bitter cold. Worth a shot. I have been saving this link for when i have time to dig into it. http://www.ford-trucks.com/forums/92...97-2003-a.html
Good luck.

 

If the axle engages when the shift fork is manually operated, the fork is ok. You either have a leaking vacuum line or a faulty vacuum solenoid on the firewall. Why not get rid of all that vacuum crap and install a cable lock? You can pick up one on ebay for about $130 and it will never fail.

 

To test mine I started the truck & had my wife turn the switch while I watched the actuator. My actuator worked but didn't engage the front axles. If i would push it in a little farther it would engage. On mine the little plastic ears on the fork broke so there was too much slop for it to engage from the actuator.

 

What do I enter in the search block on e bay?

 

Alloy USA 450750. Just checked and they have them as low as $118 shipped. I've had one for 5 years and it works perfectly.