Turning my 4X4 switch illuminates the dash indicators for both HI and Low, but the front wheels don't engage. Thoughts anyone?

 

year ? floor lever or electric switch? Manual or Vacuum locking hubs?

 

2003 Super crew ...switch on dash...must be vacumn

 

Good place to start is this thread. It gives you most if not all the possible reasons for the problem. It is the correct info for th 97-03 4x4.

https://www.f150online.com/forums/sh...d.php?t=293031

 

Ya you have vacuum locking hubs. Hearing your description and not being to actually play with the truck, it sounds like your hubs may not be engaging for some reason. The most likely is some type of vacuum leak. Crawl under the pick up and check to make sure the Vacuum lines are connected and didn't some how come off.

 

He does not have locking hubs. He has a locking diff. All locking of the front is done at the diff on the 97-03.

 

Really? How does this work? Everything I have looked up says they have Automatic front locking hubs.

 

Take a look at the thread I posted. It even has a picture on it. Also the front diff lock/unlock is not true of 04 up. They went back to hubs, but call them IWE's. Integrated Wheel Ends, made by Warn.

As far as how the 97-03 work, a quick explanation is the transfer case engages in the usual way, whether manual or ESOF. A signal is sent to one of 2 solenoids on the firewall that sends vacuum to a vacuum motor on the diff. This moves a fork that engages the diff. For coming out of 4wd, it sends the signal to the other solenoid which uses vacuum to shift the fork back.
What is at the hubs, is basically CV joints and bearings. That's it. Then front axles always move, they are just not engaged at the diff.

 

Just went threw this with my 2003 Screw. The 4x4 lights came on and i could feel the rear end get more power when i put it in the 4wd low but front diff engagement was no go. The front drive shaft spun so my transfer was fine. I thought it was the acuator at first but it ended up being the shift fork with in the diff so if your front driveshaft is spinning i would lean toward shift fork. Luckily it was covered under my extended Power Train Warranty cost 100 bucks as opposed to something to the tune of around 500 for everything i think the dealer said.

 

No sh*t ay? I really had no idea. Learn something new everyday I guess, right? :o kingfish, I do appreciate you taking the time to correct me and explain it. As I am sure you can tell, these newer Fords are also pretty new to me. Again, thanks and if I can return the favor let me know (perhaps a Mercedes question? or other European import ).

 

just ran into the same b.s. with mine. Had some bad weather here, clicked her into 4x and nothing, just alot of rear wheel spin. Got a replacement actuator, go to put it in..not the problem. The shaft that comes out of the diff is frozen, wont even try to turn. I hate this truck more and more everyday. P.O.S. ......

 

So that's what going on in there eh? Never new, I guess that's why theres no aftermarket manual locking hubs.

 

Same thing with my truck. I just replaced the shift fork on my truck last weekend. It maybe took 2 hours. Not to bad of a job. What happened was the nylon pieces on the fork broke off. Pretty poor setup if you ask me but I put a new one on. The part was only 150 bucks. The dealership said that was the most common problem on 97 to 03 F150's. Just make sure that you have vacuum at your vacuum switch on the passanger side axle and the i would tear into the shift fork. But that just my 2 cents.