Four wheel drive will not engage

Tiny
SPYAC3
  • 1999 FORD RANGER

V6 four wheel drive automatic 105,000 miles.

Hello, My truck has an automatic transmission with a turn knob switch for engaging the four wheel drive. When I switch from two wheel drive to four wheel drive high or four wheel drive lo the lights on the dash come on but front wheels never engage. I have checked all the fuses, and removed the electronic shift motor from the transfer case the motor appeared to work fine. Since the switch activated the shift motor I would guess that it is not the GEM, fuses or relays. Since this system is a "Vacuum Pulse" system is there a vacuum line somewhere that could be faulty or a o-ring that is faulty, I do not fully understand how this system works I see a lot of posts for this problem but no answers other than what I have checked. Any help is appreciated. Thanks

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Tuesday, December 4th, 2007 AT 2:54 PM

3 Replies

Tiny
FSTRANGER302
  • MEMBER

Hello, you need to find out if the front end has seals at the front wheels for the hubs if it does then you probably have a seal going bad. I hope this helps please let me know. Thanks, Pat

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Wednesday, December 5th, 2007 AT 11:22 AM
Tiny
KORNDSOILGRODOPE
  • MEMBER

Okay, to start vacuum hubs work by first when you put it in four wheel drive the engine vacuum pressures up a canister with vacuum and the vacuum stays sealed in the canister throughout the lines to the hubs, when engaged the vacuum pressure engages the hubs, but if a hose is broken the vacuum leaks out until it has no pressure and hubs unlock, I have an 1998 four wheel drive and I know this by experience. So anyone can call me on it but I found when I got mine that the right tire hub, the vacuum hose to it right where it connects to the tire was cracked and it bleed the vacuum and hubs just disengaged so to start I would remove front tires and look on inside of assembly at vacuum lines for crack or anything then if no problem trace lines to engine looking for any problem if no problem remove vacuum line from engine and see if it is even getting vacuum. Try this and get back to me.

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Thursday, December 6th, 2007 AT 12:36 AM
Tiny
ASEIDNER
  • MEMBER

I have a 1999 Ford Ranger four wheel drive manual. How I found out front wheel drive was not working was the AC would not blow into the cabin at high speed or hard acceleration. I found a broken vacuum line on the right side, so I replaced it and AC works and so does the right tire engage. My left is an issue, The left locking hub is always engaged so I will work on that this coming week. I did find replacement manual hubs at www. Therangerstation. Com (AVM Locking Hub)for $160.00, but I have not tried or bought them yet if I can not get the vacuum ones to work property. While I am on that side I am replacing the 1/2 axle it leaks and has a broken boot.

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Saturday, January 22nd, 2011 AT 2:58 AM

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