Hey guys I have manual/auto hubs but when I throw it in 4H from Neutral and have hubs set in free it's not engaging. Do I have a vacuum problem somewhere? She still works when I lock them manually but I like for stuff to work when I need it (like when I have half my truck in a lake).

 

I don't know the whole system but the first thing to check would be the vacuum lines that connect at the hub. They go from the hub to a fitting near the shock. Mine are in pretty tough shape right there and need replacing. Mine do not always engage anymore. It gets more in depth from there though.

 

4H you dont need it to be in neutral just so you know. You may have a vacuum leak though. Turn your a/c on high and see if it defaults to the defrost at all and/or when you switch into 4H.

Lines, solenoid, pump...blah blah blah

Like Jay said...check lines first. Its free and easiest.

 

Ya I thought it was shift on the fly too until I tried to do it at about 20 mph and all I heard was grinding........ It's the shifter on the floor model not the **** (I dont' think there's a difference though is there)?

 

I use my A/C every day and when I first turn it on it starts to blow from the defrost but then switches to vent after a good second or two delay.

 

It's probably the hub wheel Seals, or at least that was my experience with those Vaccuum hubs in my Ranger. I know your talking about a PSD, but The ranger, and the SuperDuty Hubs are both From WARN, and they are under the same exact Patient, and same Design, Same idea.

I personally don't use them on my PSD, when they went out I didn't even want to mess with them anymore. I just replaced mine with Warn premium Hubs because when I need 4 wheel I want it to work, and the Premiums hold up better and are easier to clean and use for me..

My 98 ranger has the same system without the Manual Overide, and I've had plenty experience with them and their problems because i didn't have the option of Puttin Manual Hubs on that truck so I was forced to go with the Vacuum Auto ones.

There is a Seal kit for them, You can also Take off the Vaccuum Line on the backside of the hub and put a Hand Vaccuum pump on them and you should be able to engage them manual with the hand pump.. If you can't pull a Vaccum on the Hub, then it's your Seals in the Bub, Wheel Seals and Axel Seals.

I think It was something like 15 psi to engage, and 30 to Disengage.. But it could be different for the PSD. Think of a click Pen, You push it down once (1/2way) to engage, and Click it again all the way to disengage... Same concept.. Instead of Pushing, you are pulling it with a Vaccuum.

Secondly If you Pull the Vacuum lines, you can put a Vaccuum Gauge on the Line and see if the computer and Vaccuum is actually pulling the right vaccuum. should pull vaccuum for 30 seconds or so..

Those Systems work great for most rigs, But when you run off road and in 4x4 as much as i did I would wear through seals in 30K miles...

They are Designed by Warn, on my Ranger, I was one of the first Failures on the system and worked with the warn Design engineers about that problem, But I was replacing Seals every 30K miles to keep them working. They actaully took my Truck and used it for a life test because I was burning through Hub seals so fast.

That's why I just went with Manual. I'll never get another truck without Manual Hubs.

Good Luck.

 

If its not a vacum leak you can try this. I put on new lines and did this to mine and they work great. I like to stay in side and get 4 wheel drive when I want it.
http://www.guzzle7pt3.com/allube.php

 

That's a Great Post with excellent Photo's, Brings back some un wanted Memories..LOL..

That proceedure will cover two of the three Seals, (O-Ring, And the diaphragm) the Third Seal which is the Axel seal can also cause vaccuum problems with the Autolock also.

But You should be able to tell Before you remove the hubs if there is a Leak in the wheel hub.. (Likely) or the Supply side with a Vacuum pump or gauge.

 

If you have a floor shifter then you don't have vacuum hubs do you? Not sure about shift on the fly with that set up

 

If you have the shifter on the floor, you don't have auto hubs or SOTF. You have no vacuum lines going to the hubs.

EDIT: Jay was faster then me. lol.

 

Open mouth.. Insert foot..

Guess I didn't read the Second post very well..

 

No problem, you did have a good post.