Dreaded PVH 4WD

[Mdeshaies]

I am the proud owner of a 1998 ranger. Unfortunately the 4WD does not work. When changing the dash switch to to 4WD and back to 2WD the dash lights change as they should so I assume the shift motor works, since the switches in it shift. So I assume it’s the @$#% hubs. Took one off and it moved freely and was not all gunked up with dirt etc. switch to manual hubs? Hear a lot off bad ju ju on those too. Any suggestions other than buy a Chevy ?

 

[Dirtman]

Check the vacuum line to the axle.

 

[fixizin]

Yep, as goofy and "Rube Goldberg" as those PVHubs are, it's usually either the lower portions of the vacuum hoses (because they're exposed to all the sand/salt/water/road grime) that partially disintegrate, and/or, less often, the very thin O-rings associated with the major hub assembly no longer seal. You can jack the front wheels off the ground, alone or together, and (if it's just the hoses) check individual PVH function with a handheld vac pump.

In the Tech Library section are excellent how-to's on removing the outer "screen-disk" cover of the PVH mechanism; this allows you to both observe vacuum collapsing the rubber dome/seal, and to manually push on that same dome to engage/dis-engage the locking mechanism. So, no need to get manual hubs, since a) you can operate the stock PVH jobbies manually; and b) the after-market manual hubs are pricey and easy to steal. The stock PVHs are actually quite strong, with lots of metal-to-metal engagement.

PS: if your 1998 still has the original shift motor--in Maine of all environs--you're beating the odds! I hangs low, is not well sealed, and that funky round printed-circuit board tends to corrode to ruin.

 

[19Walt93]

Shift motors don't often fail if they get some exercise. I had 4x4 Rangers from 2004 until 2018 with zero problems. I would engage and disengage 4x4 about once a week on my dirt road and they worked every time I needed 4x4. The PVH system had me shaking my head when it came out. We had a Ranger engineer at a parts and service managers' meeting to show off the newly redesigned front drive system. After he explained how it worked I asked why they hadn't just used the 4x4 system Explorers had introduced 3 years prior that had been flawless and he gave me a blank stare. I guess it was unreasonable for the Ranger engineers to look at what already existed instead of reinventing the wheel, never mind that the early Explorers were station wagons made out of Rangers.

 

[Mdeshaies]

Shift motors don't often fail if they get some exercise. I had 4x4 Rangers from 2004 until 2018 with zero problems. I would engage and disengage 4x4 about once a week on my dirt road and they worked every time I needed 4x4. The PVH system had me shaking my head when it came out. We had a Ranger engineer at a parts and service managers' meeting to show off the newly redesigned front drive system. After he explained how it worked I asked why they hadn't just used the 4x4 system Explorers had introduced 3 years prior that had been flawless and he gave me a blank stare. I guess it was unreasonable for the Ranger engineers to look at what already existed instead of reinventing the wheel, never mind that the early Explorers were station wagons made out of Rangers.

 

[Mdeshaies]

Thanks for the replies. I do have a question about the shift motor. Is the fact that I am getting light changes I.e. 4WD / 4WD low etc mean the shift motor is operating or do they put those lights on the dash to amuse folks like me? I assume the dash lights are driven by switches in the motor ??

 

[rusty ol ranger]

Thanks for the replies. I do have a question about the shift motor. Is the fact that I am getting light changes I.e. 4WD / 4WD low etc mean the shift motor is operating or do they put those lights on the dash to amuse folks like me? I assume the dash lights are driven by switches in the motor ??

On my 97 expedition i had the shift lights would light but do funky things (like switch off or between hi/lo without moving switch) even though the motor failed in 4 low.

 

[4x4junkie]

Thanks for the replies. I do have a question about the shift motor. Is the fact that I am getting light changes I.e. 4WD / 4WD low etc mean the shift motor is operating or do they put those lights on the dash to amuse folks like me? I assume the dash lights are driven by switches in the motor ??

You should be able to notice a dramatic change in gearing when you shift it into 4x4-Low regardless of whether the hubs lock or not. If so, then yes, the shift motor is working, and your issue would be just the hubs (also, if the lights are on steady, this is another indicator of proper operation. If the lights flash, then the shift motor likely isn't engaging correctly).

 

[fixizin]

Shift motors don't often fail if they get some exercise.

Makes sense, since the copper traces on the circuit board will get "wiped" by the contacts, preventing corrosion buildup, and likewise the brushes and commutator in the DC motor naturally keep each other clean and buffed up. I used my 4WD often 1999-2002, then rarely '02-04, then not all until one day in 2011... errrrnnnt! (hockey buzzer)... about $65 for the whole shebang w/ core trade-in... would MUCH rather have FX4 manual shifter, but...

 

[Mdeshaies]

Well I do not notice any change in gearing when I shift to 4x4 low which I tried so it looks like a shift motor to start with. And yes, I don’t see this as an improvement over the good old manual shift lever!

 

[19Walt93]

To shift in or out of low range you need to be in neutral, at a dead stop, with the brake applied, just turning the knob isn't enough.

 

[Mdeshaies]

I read the owners manual and applied the proper shift procedure with no change in gearing

 

[19Walt93]

Dos the 4x4 low light blink? If so, that's a fault indicator. You get points for reading the manual, I spend decades explaining things to customers because they hadn't read ir.

 

[fixizin]

Yeah, manual t-case shift-lever (or WORKING electric shifter) + PVH hubs = don't have to leave the dry/warm cab to engage the 4WD. A big plus when you're "dressed up" for whatever.

Can't easily adapt your t-case to take a manual lever, quite aside from the whole cutting a whole in the floor thing. Shift-motor swap not a tough job, EXCEPT... for the infamous BROWN WIRE. Take your time and work it out of the connector. Resist the urge to cut now/splice later.

OTOH, if your shift-motor is actually still turning, you may just have to clean up the circuit board with contact-cleaner, or 91% alcohol in a pinch.

Please report back--we all learn from each other's wrenchy/sparky (mis)adventures...

 

[Mdeshaies]

No the lights do not blink they stay on I.e. when I switch to 4x4 low, the 4x4 low light illuminates steady until I move the switch to a different setting. Usually the proper light lights up in a second or two which makes me think the motor is turning