4 Wheel Drive Won't Work
11-08-2009, 07:23 AM
#1
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4 Wheel Drive Won't Work
I have a 1998 F150, 4x4 Lariat 136,000 miles. The 4 wheel drive, front wheels won't engage. It has the switch on the dash, not manual hubs. The shaft off the transimission engages went I flip between 2 and 4.
The vaccum lines go to a round black unit, middle front of the front axle. Does this push/pull the axles to hubs, or what does it do? I haven't found any lines/wires to the hubs other than the anti-lock brakes. It also has a vent hose that goes up in the motor compartment.
I guess this is an education session. Where should I start?
The vaccum lines go to a round black unit, middle front of the front axle. Does this push/pull the axles to hubs, or what does it do? I haven't found any lines/wires to the hubs other than the anti-lock brakes. It also has a vent hose that goes up in the motor compartment.
I guess this is an education session. Where should I start?
11-09-2009, 10:13 AM
#2
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If your truck is like mine, then that black box on the front of the axle is the 4wd acctuator. It controls a little arm inside the axle housing that slides a lock collar onto the axles to engage the front axles. You need to make sure the acctuator is working first. get someone to switch it from 2wd to 4wd and back and forth and look at the acctuator and you should see part of it moving.
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cjc (02-03-2013)
11-09-2009, 11:10 AM
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I have a 1998 F150, 4x4 Lariat 136,000 miles. The 4 wheel drive, front wheels won't engage. It has the switch on the dash, not manual hubs. The shaft off the transimission engages went I flip between 2 and 4.
The vaccum lines go to a round black unit, middle front of the front axle. Does this push/pull the axles to hubs, or what does it do? I haven't found any lines/wires to the hubs other than the anti-lock brakes. It also has a vent hose that goes up in the motor compartment.
I guess this is an education session. Where should I start?
The vaccum lines go to a round black unit, middle front of the front axle. Does this push/pull the axles to hubs, or what does it do? I haven't found any lines/wires to the hubs other than the anti-lock brakes. It also has a vent hose that goes up in the motor compartment.
I guess this is an education session. Where should I start?
Hilarious, I came on this forum this morning because my truck (97) is having exactly the same problem. I hear a small clunk from the transfer case like it is engaging when I turn the 4x4 switch but the wheels are not turning. I will check the actuator as mentioned above.
I also have heard that there is a little servo motor in the transfer case that tends to go, anyone know anything about that?
Any other suggestions would be appreciated by more than one forum member now
Are there any fuses that might be the problem? Thanks for the help, snowmobiling season is quickly approaching so I have got to get that 4 wheel drive working.
Last edited by powderhoundbrr; 11-09-2009 at 12:49 PM.
11-10-2009, 06:25 AM
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OK, the 4wd acctuator is not moving, when the we switch between 2 & 4 wheel drive. What would be the best to check next, vaccum lines or remove the acctuator then see if the level will actually move?
11-10-2009, 09:47 AM
#5
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got a dumb question but the truck was running wasn't it lol i would check the vaccum lines next, just pull them off the acctuator (remember where which one goes) and get your buddy to do the same thing, you should be able to hear/feel the air coming in and out of the lines. If not, one of your lines might have a hole rubbed in it. The battery box in my truck rubbed a hole in one of mine one time
Last edited by my2003Fx4; 11-10-2009 at 09:50 AM.
11-10-2009, 11:36 AM
#6
got a dumb question but the truck was running wasn't it lol i would check the vaccum lines next, just pull them off the acctuator (remember where which one goes) and get your buddy to do the same thing, you should be able to hear/feel the air coming in and out of the lines. If not, one of your lines might have a hole rubbed in it. The battery box in my truck rubbed a hole in one of mine one time
Those vaccum lines are hard plastic and get brittle over time, so be careful not to bend them too much, they could be cracked anywhere so look close
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