1999 Ranger 3.0 - Auto Hubs dissengaging


cal74

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Working on a new project truck I had planned to sell, but figured I'd keep it over the winter.

Yesterday was literally the first time I've driven it more than a couple hundred yards and today was the first time I've used the 4x4 (other than checking it earlier to make sure it worked).

Shifts into 4x4 and mostly coming to a stop or even slowing down the 4x4 is disengaging. Auto hubs don't sound like they're slipping. Guessing a vacuum leak, but would it be anything else?

Thanks for any tips.
 


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RonD

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Yes, vacuum issue

1998-2000 Ranger 4WDs used Pulse Vacuum Hubs(PVH)

Each hub will have a vacuum hose to a Splitter on front axle, then a single vacuum hose from there up to the Vacuum modulator(PVH Solenoid), usually on passenger side engine bay lower down.
Modulator is what the 4X4 module uses to control vacuum going to the hubs, so it will have two Vacuum hoses, vacuum IN and vacuum Out to hubs
And it will have 2 wires

Vacuum IN comes from the vacuum reservoir, black plastic ball, also low down on passenger side of engine bay.

You can trace hoses back to Vacuum Modulator then pull off that hose and "suck on it", lol, or use a vacuum pump, it should hold a vacuum(low pressure) forever, if it doesn't then hoses or hub is leaking.

Vacuum at the Modulator needs to be tested with a vacuum gauge, $20 and every DIYer mechanic should have to test engines, still the best diagnostic tool for gasoline engine since the 1890's, lol.

If your vents in the cab are stuck on Defrost then your vacuum reservoir is most likely bad, cracked or not getting vacuum from the intake manifold, and that would effect the PVH from staying locked.


All Rangers 4WDs have an OPEN front axle, so if one hub is unlocked then NO 4WD, so both hubs need to stay locked to get 4WD.

Manual Hub conversion was popular and sometimes less expensive than servicing PVH system

PVH troubleshooting here: https://therangerstation.com/tech_library/ford_ranger_pvh_hub_operation_and_troubleshooting.shtml

Conversion to manual here: https://therangerstation.com/tech_library/AVM_hub_swap.shtml

You also have an option to just lock the hubs full time, seen here: https://therangerstation.com/Magazine/Apr04/offroad.htm
 
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Craig0320

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If you are planning on keeping the pvh hubs then I would replace every vacuum line on it. If not, then just slap some manual locking hubs on it as stated above. You could also convert it to a live axle setup.
 

Lanciadave

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Yes, vacuum issue

1998-2000 Ranger 4WDs used Pulse Vacuum Hubs(PVH)

Each hub will have a vacuum hose to a Splitter on front axle, then a single vacuum hose from there up to the Vacuum modulator(PVH Solenoid), usually on passenger side engine bay lower down.
Modulator is what the 4X4 module uses to control vacuum going to the hubs, so it will have two Vacuum hoses, vacuum IN and vacuum Out to hubs
And it will have 2 wires

Vacuum IN comes from the vacuum reservoir, black plastic ball, also low down on passenger side of engine bay.

You can trace hoses back to Vacuum Modulator then pull off that hose and "suck on it", lol, or use a vacuum pump, it should hold a vacuum(low pressure) forever, if it doesn't then hoses or hub is leaking.

Vacuum at the Modulator needs to be tested with a vacuum gauge, $20 and every DIYer mechanic should have to test engines, still the best diagnostic tool for gasoline engine since the 1890's, lol.

If your vents in the cab are stuck on Defrost then your vacuum reservoir is most likely bad, cracked or not getting vacuum from the intake manifold, and that would effect the PVH from staying locked.


All Rangers 4WDs have an OPEN front axle, so if one hub is unlocked then NO 4WD, so both hubs need to stay locked to get 4WD.

Manual Hub conversion was popular and sometimes less expensive than servicing PVH system

PVH troubleshooting here: https://therangerstation.com/tech_library/ford_ranger_pvh_hub_operation_and_troubleshooting.shtml

Conversion to manual here: https://therangerstation.com/tech_library/AVM_hub_swap.shtml

You also have an option to just lock the hubs full time, seen here: https://therangerstation.com/Magazine/Apr04/offroad.htm
Thanks Ron D, that is exactly what I was looking for.
 


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