Hi everyone,
I have a 1998 supercab 4.0 Ranger 4x4. It has the electronic transfer case and pulse Vac locking hubs. My question is are the hubs supposed to unlock when the truck is reversed or are they supposed to unlock when the 4x4 switch is put back in 2wd?? My truck will NOT unlock at the hubs unless I reverse for a good 15-20 feet or so.
Thanks for the help,
-Phil

 

Hi Phil!

There have been a ~ton~ of discussion on here - even just recently - about his topic. You may want to check the archives for indepth info but the short version is this:

The should unlock when you flip the switch. It may actually take a few seconds but moving the vehicle should not normally be necessary ~at all~.


If they are not simply dirty or have damaged seals (only semi-expensive), you will need to grab your piggy bank and go to your mechanic. You are about to spend some serious money.

FWIW -I feel your pain. I have the same truck.

 

I LOVE my truck to death, don't get me wrong. It has served me well and has never given me any problems. But this hub thing is killing me. What should be my first course of action for this? Are the hubs bad? I know that it isn't the valve because if I unhook the vac line the hubs won't unlock. Thanks for your reply and any future replies.
-Phil

 

Does the 4x4 Hi light go out when you switch the **** back to 2wd? or does it stay lit until you reverse the truck? Im just curious, I dont have any good suggestion yet.

 

I guess becuase I am used to the old locking type hubs, I always back mine up 10 ft or so just for good measure. Even though I should have too. lol

 

Yes, when the 4wd mode switch is moved back to 2wd the light goes out.
-Phil

 

Fordman,

With the PVH system on your '98, the light on the instrument panel does not indicate proper or improper 4x4 engagement ...it simply lets you know that the switch was turned, nothing else. So it's different than the earlier 4x4 engagement systems in that regard.

If you read through this thread you will get a very good understanding of how the PVH system works:

'98-'00 4x4 Pulse Vacuum Hubs

Since disengagement of 4WD in the PVH system requires that vacuum be applied to the hublocks for 10 seconds, my guess is that on your truck the disengagement is not happening immediatly upon the switch being turned. Quite possibly, it's taking all 10 of those seconds to complete the transfer back to 2WD. Do you wait a few moments after switching before concluding that you need to do more to get it out of 4WD?

I could be wrong, but I don't see how putting the truck in reverse would help to finish or complete the transfer ...I'm not trying to suggest that it doesn't work like that in your case, but what I am saying is, based on thow the system is designed, it shouldn't.

 

Rockledge, you Da Man! What a GREAT contribution!!

. . anyway, what my tiny mind was thinking could be summed up in one word (that is probably not surprising ):

Contamination.

There is gunk in there holding up (delaying) the locking/unlocking.

Dang, poor guy can't very well take all that stuff appart and clean it like in the good old days. Sometimes, progress STINKS

 

So you think that I may have some dirt in my vac lines preventing it from releasing the hubs. What should I do to repair this situation?
Thanks,
-Phil

 

Well . . . ok, you asked

I think there is either 'mud' inside the hub(s) or water has washed the lubrication away, or a combination of both.

I want to be the first to point out the apparent hole in my theory:

There are seals (wimpy as they may be) that prevent this AND allow the vacume to actually operate the hubs.

. . I'm saying that theoretically if there was mud in the hub it shouldn't lock - or unlock - period because the necessary vacume could not be achieved due to the [u]leaking seal(s)[/].

However . . .

If we are talking about siltty mud, or just plain old water, a very small leak could slow the hub engagement/disengagement without stopping it AND allow the hub lubrication to be washed out (or contaminated the the point of failure) culminating in exactly what you are experiencing. . . or worse.

Thus, the first step is to take the dang things off and have a look at them. Unfortunately the "Better Idea" Ford had in this case was to design a hub/wheel bearing ASSEMBLY that requires a significant chunk of change to change.

. . . pretty cheap to look at, though.

If you play by "the rules", there are some o-rings (that may well be your problem) that are supposed to be changed every time you "open the hubs". They are not expensive . . compared to the hubs.

In closing, please remember, there is a bunch of opinion above. In the end it may well be worth every penny paid for it

HTH.

(ON EDIT: "up above" meaning within MY post)

 

Well guys, it was a nice day here in Rochester so when I got home from college I started to screw around with it. I started by attaching my vac. guage to the PVH solonoid and flipped the switch to 4 high. I found it would supply about 23 Inches of vacuum for 60 seconds. When I switched it back to 2wd. the vacuum would read about 7 inches for 11 seconds. I then unplugged the guage and attached a vac pump to the hubs and applied the 23 inches and the hubs lock. All good so far. Then I dumped the vacuum and brought it up to 7 inches then dumped it and the hubs released. I did it about 10 times and they released every time which leads me to believe my hubs are fine and that my solonoid is going. After I got everything back together I road tested it and it was doing the same thing as before. But now if I stop and then shift it back to 2wd the truck will release the hubs but only if the hubs are not spinning. If they are spinning they won't let go.
Any ideas?
Thanks for the help again guys,
-Phil