Hey Folks, new to the forum and damn glad to be a member! Just got the truck back from the shop and I'm told my 4WD is stuck on. 2003 F150 Lariat 5.4/ FX4. The dash light isn't on and the switch is in 2H position. When I flick the switch I can hear it clicking and the dash light comes on. Mechanic tells me the front wheels are engaged though. I'm thinking a vacuum problem? My EATC hasn't been working for a few months, wonder if that has an affect on vacuum. It will barely blow any air no matter how high the dial is set.

 

Get under the truck and move the transfer case linkage manually. Also check the vacuum solenoid on your front diff (a plastic shield will have to be removed). There are 2 vacuum lines - with the 4WD off, there should be vacuum on the pink line. With it on, it should have vacuum on the blue line. If it's a vacuum problem you could reverse the lines to disengage the shift fork as a temp fix.

 

You can get rid of all that vacuum crap and replace it with a cable lock for about $125. Much more dependable. You'll have a **** that you'll pull out about an inch to engage the front end. Something else that's notorious for fouling up on your truck is the electric shift motor on the transfer case. No quick fix or bypass for these, you have to replace. You need to figure out whether its your front end that's engaging or your transfer case.

 

Great advice, thanks! At the very least I will be more educated next time I speak with the mechanic.

 

Tell me more about the cable system!

 

Its a very simple system to install. You remove the vacuum actuator on the front axle and unplug the vacuum solenoid electrical connections on the firewall. Drill a hole through the drivers side lower firewall and route the cable to the front axle. Mount the cable with the supplied hardware and that's all. Comes with detailed instructions. Its much more reliable than the factory system and cheaper than replacing the factory components.

 

Alloy USA part# 450750. On ebay for $118

 

What does your truck do that made you take it in

 

I have key on, put truck in neutral, switch your 4x4 switch to 4l then back to 2wd and then put her back in park start her up and drive, I've had this problem many times when I put my truck in 4l

 

Have not seem that before - seems like a good solution.