I have a 99 4x4 F150 with problems shifting front differential into 4x4. It has the shiftonfly dial on panel and everything works except the front diff wouldn't kick in. The archives lead me to believe the vacuum motor located on the diff was the culprit so I ordered a new one that arrived today from OnlineFordParts, a good outfit to deal with. Someone stated it was a 15 minute job to change out. HA! HA! More like 4 hours. The problem is that up here in Michigan we get megatons of salt on our roads all winter and it corrodes the heck out of everything which resulted in a lot of work getting the old vac motor out of which I buggered up real good, or is it bad?
Anyway, the reason for this post is to let those know who haven't had the problem YET that the vac motor was fine. I say "was" because it isn't anymore after I got through with it. The problem was the shift lever shaft was real tight and the vac motor didn't have the power to move it. The fix was to put a 16 inch piece of pipe over it and work it back and forth while spraying chain oil around the shaft area. After about ten minutes of this it finally loosened up nicely so that I could install the new vac motor. Everything is fine now and it shifts like it did when new. This reinforces the theory that it pays to shift into 4x4 periodically to keep things loosened up of which I'm now convinced is a good thing.
Thanks to all those who posted on this subject so I could do the job myself and save muchomegabucks. Maybe I'll reward myself and buy something nice for Christmas FOR ME!
Happy Holidays...
Darrel
"I'd rather be flying"

 

I have a 2001 F-150 4x4 that does not shift into 4 wheel drive. I took the cover off the vacuum motor and tried to remove it to no avail. How does it come off? How much is one and where do I get a new one if I break this one? Do the vacuum lines just come out?This is my first electris 4x4 so sorry if I sound ignorant. thanks for reply.

 

defrieszel,

don't be too quick to blame that vacuum motor!

first be sure you are switching the vacumm lines coming to it.
it has two lines, one always has a vacuum pull on the motor. unhook them and have someone switch the control for you and see if they switch vacuum from one to the other.

the control valves are up on the firewall behind the battery and like I said they flip flop state when the dash control goes from 2 to 4 wheel drive.

I just yesterday had this happen to my truck and had to trouble shoot the system to find out how they operate. Also the two valves are not the same, they look the same, but the electricial connectors are keyed different The one on the left(as you face them) pulls to lock the front diff. and the one on the right pulls to unlock the diff.

they were not a parts house item, and you have to go to Ford for them, or a junk yard like I did.

Gene

Yes they just pull off the motor, remember which one is which, they are color coded

 

Can you give a bit more detail on where the vacuum moter and the lines are located?

Thanks

 

Sure Boston,

The switching vaccum motor location is on the front diff. of coarse, on the right (passenger side) of the gear set. Its has a black plastic shield over it to keep oil from falling on it when the oil filter is changed. Three 10mm bolts hold it on and you can see it if look up under this shield. The two vaccum lines run along the axle to the frame in split loom conduit and then up towards the valves that are on the firewall just behind the battery. It looks just like any other vaccum device with a rubber boot covering the shaft and linkage to the lever that enters the front diff. to do the shifting of the sleave that locks the two front axles together.

Hope that helps!

Gene

 

I am having the same problem with my 97 ford 4x4. It will not engage my front drive train. I was wondering if you were able to put your truck in low range and drive it in low with only two wheel drive. I am able to do this, I am just trying to narrow down my problem furture.

 

Got mine fixed today. After hours of frustration and talking to lots of people, I found the problem to be vacuum lines. They were broken in several different places so I replaced all the plastic crap with rubber vacuum hose. I rerouted them out of harms way. Thanks to everyone who posted a reply.

 

sfoner: Does the 4x4 light come on? If not, it is the switch on the front of the transfer case (if you have the manual shift model). The switch costs about $25 and just screws into the case. It has an electrical connection with 2 wires running to it. The part number is on the switch.

Good luck.

dbh