Front axles turning in 2wd

[Uncle Gump]

This is EXACTLY why I asked @StanC to post his own damn question in the first place.

 

[StanC]

Gentlemen, thanks for all the replies.
snoranger That's the post I am speaking of, the F150 or expedition. I know this is a Ranger forum but this is where I saw it. I have been chasing this issue for about 3 weeks since I got the vehicle. I have a 2017 Expedition Limited. It has IWE vacuum locking hubs. I have a hum at highway speed in 2wd. Basically Everything works as it should but my front axles turn when driving in 2wd.
This is what I posted in the expedition forum.
To double check the IWE's and the hose leading to them I used the vacuum line at the IWE solenoid to pull vacuum to both IWE's and it held at over 20in for 20 minutes, wheels spin without turning axles, until I disconnected my vacuum pump then the wheels are connected to the axle shaft as they should be. Then I connected everything back and pulled the line off the reservoir, vehicle off, and there was existing vacuum there. So I believe the check valve is working. It seems like everything is working as it should. I even confirmed the front drive shaft is free when in 2wd with the vehicle running by rotating by hand. The problem is I get a noise from the front end when driving, sounds like a wheel bearing. I installed a new motorcraft hub/bearing on the drivers side and the noise is the same. So I mounted a GoPro to the frame and drove around and found out the axle shaft is indeed turning with the wheel when the vehicle is moving and in 2wd. But I noticed that the axle would stop spinning for a second when I was doing a full turn like in a parking lot. And sometimes the axles did not seem to be turning at the speed the wheels was turning. I assume the axles spinning at highway speed is where the noise is coming from. Any ideas as to why the axle shafts are turning if everything checks out?

I did not get any replies from the expedition forum guys then I found Jim's post and it was the same issue.

 

[G8orFord]

Nothing on any pre-2011 resembles what you have on a 2017 Expedition. Not sure about the new Rangers.
Assuming the 2017 was still using the same basic system as earlier F-150s & Ex's, the front axles do turn all of the time. The vacuum actuator is actually on the differential and simply connects the differential to the already turning axles.

 

[StanC]

I had that on my 1997 F150 but I believe the newer models do actually disconnect at the hub and the transfer case.

 

[G8orFord]

The newest model I've looked at was a 2011, I think, so that's entirely possible.

Should be fairly easy to check, if there's a vacuum line at the hub, then it's vacuum actuated. If not, it's probably always connected.

 

[Snoranger]

Gentlemen, thanks for all the replies.
snoranger That's the post I am speaking of, the F150 or expedition. I know this is a Ranger forum but this is where I saw it. I have been chasing this issue for about 3 weeks since I got the vehicle. I have a 2017 Expedition Limited. It has IWE vacuum locking hubs. I have a hum at highway speed in 2wd. Basically Everything works as it should but my front axles turn when driving in 2wd.
This is what I posted in the expedition forum.
To double check the IWE's and the hose leading to them I used the vacuum line at the IWE solenoid to pull vacuum to both IWE's and it held at over 20in for 20 minutes, wheels spin without turning axles, until I disconnected my vacuum pump then the wheels are connected to the axle shaft as they should be. Then I connected everything back and pulled the line off the reservoir, vehicle off, and there was existing vacuum there. So I believe the check valve is working. It seems like everything is working as it should. I even confirmed the front drive shaft is free when in 2wd with the vehicle running by rotating by hand. The problem is I get a noise from the front end when driving, sounds like a wheel bearing. I installed a new motorcraft hub/bearing on the drivers side and the noise is the same. So I mounted a GoPro to the frame and drove around and found out the axle shaft is indeed turning with the wheel when the vehicle is moving and in 2wd. But I noticed that the axle would stop spinning for a second when I was doing a full turn like in a parking lot. And sometimes the axles did not seem to be turning at the speed the wheels was turning. I assume the axles spinning at highway speed is where the noise is coming from. Any ideas as to why the axle shafts are turning if everything checks out?

I did not get any replies from the expedition forum guys then I found Jim's post and it was the same issue.

Last time I talked to him about it... he just leaves it in auto 4wd. It doesn’t make any noise with the the IWEs engaged.

 

[JohnnyO]

Auto hubs usually fail and won't lock. Warning signs are when they start buzzing. The vacuum hubs are notoriously unreliable, and that is why Ford went live axle after only 2 or three years.

AJ

I don't think it was even that long. I'm sure it's in the Tech Library someplace but the pulse vacuum hubs came out in 1998 and as I recall Ford scrapped them and went to an always-live front axle halfway thought the 2000 model year.

Permanently Lock Your '98-'00 PVH Hubs - The Ranger Station

In the ’98 model year Ford gave us Ranger enthusiasts a couple of body blows. Not only did we lose our reliable and easily modified Twin Traction Beam suspension, but we also lost the ability to slap on a … Continued

www.therangerstation.com

 

[Uncle Gump]

I don't think it was even that long. I'm sure it's in the Tech Library someplace but the pulse vacuum hubs came out in 1998 and as I recall Ford scrapped them and went to an always-live front axle halfway thought the 2000 model year.

Permanently Lock Your '98-'00 PVH Hubs - The Ranger Station

In the ’98 model year Ford gave us Ranger enthusiasts a couple of body blows. Not only did we lose our reliable and easily modified Twin Traction Beam suspension, but we also lost the ability to slap on a … Continued

www.therangerstation.com

So from 1998 to halfway through 2000... isn't that like... 2 or three years?