Four Wheel Drive

[VampishRogue77]

I have a 99 ranger which recently lost four wheel drive due to the vacuum system not working as it should. I just tried to bypass the whole system by just locking the hubs. However, after doing this, while in four wheel drive even with the hubs locked after a couple minutes and I let off the gas the truck is back to two wheel. If I switch out of four wheel and then back in it re-engages as it should but yet again kicks me back into two wheel again after a couple minutes.

 

[ericbphoto]

How are you locking the hubs? I’m pretty sure that is the only part of the system that uses vacuum. The transfer case is shifted by an electric motor. If you have converted to manual hubs, somehow, then vacuum is not needed for 4x4 operation.

 

[RonD]

Welcome to TRS

Yes, 1998-2000 Ranger 4x4s used Pulse Vacuum Hubs(PVH), not one of Fords best ideas, but not the worst either, lol

Most remove these hubs and install manual hubs, AVM470: https://www.therangerstation.com/tech/1998-2000-ford-ranger-manual-locking-hubs/
Sold as Rugged Ridge, Mile Marker and AVM
AVM makes this model

But you can try locking what you have, seen here: https://www.therangerstation.com/tech/permanently-lock-your-98-00-pvh-hubs/

Or this way: https://www.therangerstation.com/tech/adding-manual-control-to-your-1998-2000-ford-ranger-pulse-vacuum-hubs/

All Ranger 4x4s have an OPEN front differential, what that means is that if ONE hub unlocks then BOTH front wheels are without 4WD power
So you have to make sure both front hubs stay locked
It reads like one of your front hubs is unlocking when you are using it in 4WD

 

[VampishRogue77]

Welcome to TRS

Yes, 1998-2000 Ranger 4x4s used Pulse Vacuum Hubs(PVH), not one of Fords best ideas, but not the worst either, lol

Most remove these hubs and install manual hubs, AVM470: https://www.therangerstation.com/tech/1998-2000-ford-ranger-manual-locking-hubs/
Sold as Rugged Ridge, Mile Marker and AVM
AVM makes this model

But you can try locking what you have, seen here: https://www.therangerstation.com/tech/permanently-lock-your-98-00-pvh-hubs/

Or this way: https://www.therangerstation.com/tech/adding-manual-control-to-your-1998-2000-ford-ranger-pulse-vacuum-hubs/

All Ranger 4x4s have an OPEN front differential, what that means is that if ONE hub unlocks then BOTH front wheels are without 4WD power
So you have to make sure both front hubs stay locked
It reads like one of your front hubs is unlocking when you are using it in 4WD

I locked the original hubs and they are both locked however it will not stay in four wheel drive. It will engage whenever I put it in four wheel drive but a couple minutes later it disengages again. Must be something electrical?

 

[RonD]

Does the 4High or 4low light go OFF when it comes out of 4WD?

Assuming electric shift
The shift motor on the transfer case uses a worm gear drive so can't slip unless drive is broken
Inside the shift motor assembly are 4 position sensors that tell the 4x4 controller(GEM Module) what position the shift motors drive is in which should be what position the transfer case shift rod is in, 2H(2WD), 4H or 4L
Position sensors are what activated the lights, via the GEM, there are no sensors inside the transfer case

Position of shift rod seen here: https://www.therangerstation.com/tech_library/images/rebuild_transfer_case_shift_motor/rebuilding_a_ford_transfer_case_shift_motor-2.JPG
Shift rod is pointed at 2H in the picture

Its possible for the 4 position sensors to be "off" a little
So when 4H is selected the shift motor moves to 4H but its not fully in 4H, just on the edge of 4H, so it can "slip out" of 4H

You can remove the shift motor and plug it back in, then select 4H on the dash switch and see if the triangle drive is correctly pointed or if its off a few degrees
Also check that the triangle drive is not cracked or other wise loose

You can also use vise grips to manually turn the shift rod to 4H then clamp or tie the vise grips into position to hold the shift rod, it WILL move back to 2H on its own, there is a spring inside transfer case
Then go for a drive and see if it still "pops out" of 4H, if so then problem is in the transfer case, it will need to be pulled out and repaired

Its a BW1354 transfer case if you want to see what inside it

 

[VampishRogue77]

Does the 4High or 4low light go OFF when it comes out of 4WD?

Assuming electric shift
The shift motor on the transfer case uses a worm gear drive so can't slip unless drive is broken
Inside the shift motor assembly are 4 position sensors that tell the 4x4 controller(GEM Module) what position the shift motors drive is in which should be what position the transfer case shift rod is in, 2H(2WD), 4H or 4L
Position sensors are what activated the lights, via the GEM, there are no sensors inside the transfer case

Position of shift rod seen here: https://www.therangerstation.com/tech_library/images/rebuild_transfer_case_shift_motor/rebuilding_a_ford_transfer_case_shift_motor-2.JPG
Shift rod is pointed at 2H in the picture

Its possible for the 4 position sensors to be "off" a little
So when 4H is selected the shift motor moves to 4H but its not fully in 4H, just on the edge of 4H, so it can "slip out" of 4H

You can remove the shift motor and plug it back in, then select 4H on the dash switch and see if the triangle drive is correctly pointed or if its off a few degrees
Also check that the triangle drive is not cracked or other wise loose

You can also use vise grips to manually turn the shift rod to 4H then clamp or tie the vise grips into position to hold the shift rod, it WILL move back to 2H on its own, there is a spring inside transfer case
Then go for a drive and see if it still "pops out" of 4H, if so then problem is in the transfer case, it will need to be pulled out and repaired

Its a BW1354 transfer case if you want to see what inside it

Thank you. The 4wd light does stay on when the truck seems to “slip” back into 2wd.

 

[RonD]

So the shift motor is not moving
That narrows it down to not being in 4H fully(position error) or internal transfer case issue, shift fork is slipping maybe

 

[00t444e]

First get rid of the junk auto hubs and swap to manual ones. Then get rid of the junk electric shift transfer case and swap to a manual one, I did that to mine and it was the best modification by far.

 

[fastpakr]

First get rid of the junk auto hubs and swap to manual ones. Then get rid of the junk electric shift transfer case and swap to a manual one, I did that to mine and it was the best modification by far.

That may be your opinion, but there are two things to consider before offering your advice.
1) Lots of people regularly use their auto hubs and electric shift transfer cases, and get good service out of them for years (decades). Particularly the transfer case.
2) Calling things junk and telling someone to swap it out as a knee jerk response when someone is looking for troubleshooting information is wildly unhelpful. If that's your only available response to the thread, save your time and expend it on a thread where you can contribute.

 

[ericbphoto]

Not everyone has the resources to swap everything out instead of troubleshooting and repairing.

 

[racsan]

I had a electric shift t-case in my ‘93 and never had a issue with it, the auto hubs however proved to be unreliable and were tossed in favor of mile marker manual hubs. I did break one of those but considering the circumstances, it wasn’t suprizing-plus if something had to be the weak link then thats the easiest thing to take care of.

 

[sgtsandman]

Not everyone has the resources to swap everything out instead of troubleshooting and repairing.

Or the money.

 

[RonD]

+1 ^^^
My 1994 4x4 autohub/electric shift is still working, although I have serviced the autohubs(clean/lube when doing the brakes) and rebuilt the shift motor over the years

Would manual hubs and manual transfer case be more reliable without any servicing, yes, of course
But my electric version has never let me down, but I have never let it down either, lol

 

[ericbphoto]

Or the money.

In my book, that's a primary resource and it's usually scarce.

 

[sgtsandman]

In my book, that's a primary resource and it's usually scarce.

You can read?!?!