RadioMan

MCDavis, I stand corrected! The noise I was hearing was coming from both front hubs. He said I was VERY lucky I didn't keep driving it that way and got it repaired right way... It was a $12.80 Check Valve (AL3Z*19A563*A VALVE) Located under the electric switching valve.. It would not hold full vacuum when tested. All this is located at the master brake area under the hood.

I learn something new everyday.. I'm glad you pushed me into finding out how all this works... I still say Ford engineers should have developed the system opposite what it is now...

We may call them "Stealships" but I'm sold on using them now! Just think what it could have cost if you took it to a private repair shop. I'm sure they would have spent hours and hours looking for the problem and changing parts..

Thanks again!

Bryce919er

If they did it the other way, instead of your thread we would be reading one from someone else about how those damn engineers made it so if you loose vac you loose 4x4 & then get stuck wheeling after you snag a line. Even better, another poor driver did not know vac was out, shifted to 4x4 on a snowy road, did not find the traction they thought they would have, gets hit by oncoming traffic, & sues said FoMoCo engineer.


The hubs end up engaged as the failure method--BFD. That is the better option. Both 2WD & 4WD work after failure that way--the other way they don't. No different than driving around with manual hubs locked in which I used to do from about October to April every year. Further, my auto 4x4 GM has the hubs engaged anytime it is in auto 4x4 vs 2WD (& you can hear that it is so). I assume auto 4x4 Fords (Lariat & up) are similar.

RadioMan

To tell you the truth Bryce919er, I'll take manual hubs and the old stick on the floor over vacuum and/or electric control any day. Less problems..

RES4CUE

I agree and you still had shift on the fly if you just left the hubs locked. Lol