Hey guys,

I purchased a 98 f150 in December and it’s not going into 4x4 high or low. The light on the dash turns on and it’s sounds like It’s shifting into 4x4 but only rear wheels turn. Any suggestions?

thanks
Pat

 

Vacuum operated front axle Actuator operation has a fault if the Dash light comes on.
The system has no way to tell if the axles are locked in the front.
It maybe the firewall solenoid, the Vacuum lines to the Actuator , the Actuator or the internal yoke that slides a splined collar to link up the passenger axle halves.

 

So, Blue - I think you're saying there may be a blocked vacuum line? (One that prevents the vacuum from being released?) I ask this, because the system goes INTO 4WD if there's a vacuum leak, as I understand it.

Couldn't this just be a stuck/faulty valve?

- Jack

 

Jack, you may be confusing this system with your IWE system. The differential lock on the 97-03 is positive vacuum actuated - there are 2 solenoids, one for engage and the other for disengage. Put it in 4wd, there will be vacuum at the engage solenoid, put it back in 2wd and there will be vacuum at the disengage solenoid.

To rule out the transfer case, put it in 4wd and verify the front driveshaft turns when you move the truck in gear.

I can't find the article here, but here is one on another forum:

https://www.ford-trucks.com/forums/9...97-2003-a.html

 

I honestly am bad when it comes to working on trucks, and cars. Is it easy to find the area the driveshaft would be turning?

 

This video has a lot of good information about how 4wd is controlled.

 

Please don't take offense, but if you have to ask that question it would be wise to take it to a shop for diagnosis and repair, or at least get a mechanically inclined friend or acquaintance to help you.