I put my 98 f150 5.4 4r70w into 4wd low to back up a small steep hill to park. When I went to leave a couple of hours later, it would not shift back out of 4 wheel low...iI drove it a block or so, switching it back and forth to 2wd, finally it switched to 4 wheel high..I drove it another 100 yards or so and it finally dropped into 2wd. Is this a common prob? Any suggestions as to why it did this?

 

dou you have electric or manual shift if it is manual you are not alone it happens to me a lot

 

If E-Shift, than yes. The motor is sticking I was told. Mine will click and click and click til it finally engages/disengages..

 

Beware, the center axle disconnect. The pins on the phoney aluminum shift fork wear off and the axle won't disengage or engage properly. Ford sells a kit for circa $140.00 I believe. It is made of steel. There is a thread here somewhere that describes in detail how to replace it yourself. I chose to pay a shop to do it. Figure 3.5 hrs. labor. Of coure, it could be a weak servo, or leaking vacuum line or other things like a bad solenoid.

 

Check the vacum switches mounted on the firewall on the passenger side in the engine compartment. If you detach them from the firewall (push them down to unclip). There are two of them side by side. They develop cracks in the back of them and it causes the exact problem you descibe. There will be two vacum lines and a plug attached to each. Beware they look almost identical but they are not. The plug is slightly different on each. Love my 98 4x4. Just rolled 190Kmi with no major problems. Never getting electronic switch again though. It went a couple years back and it was some sort of relay on the firewall. The light came on but no power. Left me axle deep in a corn field with a bunch of Chevy lovers that pulled me out...SIGH!

 

Don't get ticked because I am asking this, but I have to. Were you stopped, foot on brake, and in neutral when you tried to shift out of 4lo? If no, that is why. If so, I would suspect a problem with either the senors or the brake light switch. That or a problem with the motor that shifts the transfer case in and out of 4x4.