Just purchased a 1999 4.0L 4WD, when I select 4WD Hi or LO sometimes it will go, sometimes it won't. Now the 4WD Hi and LO lights are flashing intermittently while I'm driving. At one point the Hi light burned and wouldn't turn off. Any ideas on where to begin or other had similar problem? Thanks in advance.

 

I just fixed my 4WD. MY truck is a 99 3.0 5spd. I had problems with the hubs engaging but I could hear the transfer case clunk in and out. I finally discovered the vacuum line to my passenger front hub was shot. I cut off the split end and rerouted and had 4WD just in time for the first snow here. Good luck!

 

Well now it will not go in at all. I've reset the computer and lights stopped flashing but when I engaged the 4wd the Hi light came on and stayed on but the truck doesn't shift into 4wd. After a few minutes of this the lights start flashing again. I've read a lot about this problem on here...wondering if anyone else had has this type of problem and if it sounds like a sensor issue?

 

I removed both speed sensors, the one in the rear differential and the one on the transmission, took out shifter motor gear and lubed, reset computer and now the 4wd works, it will not shift on the fly and there is a slight delay but it goes. I'm going to leave well enough alone..

 

Hey Aquaman, I think this is the problem I have with my Ranger currently. Can you go into detail about how I should go about replacing the vacuum lines? (like where to get the lines** and what you meant by "rerouting" I have replaced just about everything else and this is the most likely cause of my problem. So in short how do I need to replace the lines?

 

FixMyRanger,
I did not replace my lines due to a lack of fundalation. If you look at the back of your hub you will see a vacuum line running from the front of the truck clipped to the frame rail and going to the hub. My line was just old and dry rotted( i believe that is the correct term) so I cut the cracked end off of it, took it off the clips due to its decrease in length and pressed it back onto the hub. When I say rerouting i simply meant taking it off the clips and positioning it out of harms way for now. I am sure this is a temporary fix, but i would imagine you can get the lines at your ford dealer or a good parts store. Sorry if this isnt as helpful as you were looking for. I will post again if i look into the problem again in the near future.

 

Smythcountry - There are two threads in the stickie section about servicing the transfer case and the shift motor. I somtimes have the clunk in the transfer case when engaging particularly if I have not operated it for over a month. I try to make a habit to cycle the 4wd on/off at least once per week to help keep things "flowing".

Aquaman, from other threads I've researched, I believe the vacuum line is 3/16" fuel line tubing if you want to replace it. Can you comment about the condition of the steel tubing at the hub? Mine is severly corroded and I am worried to even attempt to push replacement tubing on it for fear it will just crumble. My truck is same vintage as yours. Thanks.

 

It wasn't very corroded. Perhaps you live somewhere that the chemicals they put on roads are hard on the metal. It was of coarse a little corroded, but not to the point where I questioned its integrity. They do feel flimsy though, so definitely take care when pushing the tube on or pulling it off.

 

I am happy to announce that today I have successfully trouble shooted/diagnosed/fixed my PVH system! It took a lot of reading on forums likes these and a faith in finding the problem instead of deciding to just go ahead and switch to the manual AVM hubs! Thanks for all the information you have provided for I have probably used bits and pieces of most peoples insite to either find the problem or eliminate the possiblility of others.

In the end we found it to be this. I have a leak in the mainshaft seal on the driver side. When that seal failed it had caused the vacuum system to fail. When one hub does not get locked in the other wheel will not get power (thanks brianjwilson for that info it really helped out today) the transmission shop had simply said it was the hubs that went bad. So I had ordered and replaced both hubs not knowing exactly what was wrong. We then replaced all the o-rings and seal and we had instaled the seal incorrectly. SO we thought we sovled the seal problem but created another but not installing the new seal the correct depth. We had tested the vacuum lines and found them to be holding vacuum as they should. Today we were able to pin point the leak to how we installed the seals and were able to correct the problem. Nothing was ever wrong with 1. the hub bearing 2. the lockout hubs 3. the vacuum line 4. the vacuum solenoid 5. transfercase/differential...but indeed it was the main seal. For more specific information of how we installed the seal incorrectly ask. I dont feel like explaining it tonight. ha. All I do know is, is that my 1999 ford ranger with pvh hubs has been fixed and will hopefully last many years.

again thanks!
Josh

 

Did you do anything about that short piece of steel vacuum tubing right at the hub that was corroded like mine?

 

Luckily the tubes you are talking about are in pretty good shape on mine. I did notice that they are pressfit instead of threaded which would almost mean you would have to take it to ford to get them replaced. I plan on coating mine with a rust reformer to slow down the process because I can see how it may cause problems. I really odnt know what else to tell you other than you may have to call ford and see if that is something they can fix for you. surely you wouldnt need to replace that whole setup...that seems a bit ridiculous.

 

I wouldn't be surprised if you did have to replace the entire hub assembly. I just had a wheel bearing go out and had to replace that, unfortunatly i didn't replace my seals so now i need to fix those in order to get my four wheel drive back. It never ends...

 

Im just trying to clarify. Did you intend your comments to me? I did mean tubes but I should have called them metal nozzles? IDK but in any case I did replace both of my hubs and o-rings and the shaft seal. My only potential weak point of the vacuum lines themselves but ill be able to figure that out pretty quick if they ever give out.

 

im having the same problem did you find a fix it would help me a lot my dad gave me a ranger.

 

Yes I did. It was the little electric motor that engages the transfer case. It was working part of the time. It was $70 at the parts store. Not sure if that will be your fix but that's what did it for me.