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