I have a 99 ranger 4.0 auto 4x4. I have been having problems with the hub on the passenger side not unlocking. Eveything else works fine the 4x4 works and thedrivers side seems to be working properly butfor some reason the passenger hub will engage but won't disengage automatically. I can do it manually though what are everyones thoughts?

 

Welcome to the forum

On most automatic hubs you have to back up as much as 75ft to unlock the front hubs.

Pulse Vacuum Hubs(PVH) were only used for a short time, reason being, too many service repairs under warranty, 1998-2000.
Ford switched to "Live Axle" as early as 1999 on some Rangers, official switch was 2001 model year, so I assume they knew the system would be trouble prone even before the first 1998 Ranger rolled out.

Have a read here on troubleshooting the PVH system: Ford Ranger How To: Troubleshoot/Fix Your PVH Hubs (1998-2000)

And know going in that any fix is temporary with PVH.

Best fix is switching to manual hubs: 1998-2000 Ford Ranger Rugged Ridge (AVM) Locking Hubs

Or locking both front hubs permanently, "Live Axle" : Permanently Lock Your 1998-2000 Ford Ranger PVH Pulse Vacuum Hubs
Make your 1999 into a 2001, lol.

 

Thank you I have been watching youtube videos on the different issues. I may just have to go with manual hubs 😕

 

In my opinion, long term that would be the best option.

Spending a hour or two now to fix current problem is fine, but there will be more problems to come, no IF about it, just a WHEN.
And the worst is when you NEED 4WD and don't have it, unexpected snow or ??.

The AVM hubs run about $100 now in ebay, so not too bad for some piece of mind

These hubs have been around awhile so turn up at wrecking yards, you can get new o-rings at auto parts stores

 

When you convert from the pvh hubs to the manual hubs do you need to plug off the vaccum lines or just swaphubs and go on?

 

I would trace the soft/flexible hoses back to hard line and cap them there.