[Mdub707]

The auto 4x4 will not work in my truck. I brought it to the dealer once, and under the powertrain warranty they replaced both front hubs, one wheel bearing and one seal. I picked the truck up and the auto 4x4 was still not working as I pulled out of the parking lot. I just have not had time to get it back to the dealer, I did tell them it wasn't working. Anyways, I'd much rather just fix this myself if it's inexpensive so I don't have the down time with the truck. It is now over the 60k miles for the powertrain warranty, though I think they would honor it since they never fixed it originally. Anyways, any thoughts on this? If you get out and turn the hubs, the 4x4 works from inside the cab then...

 

[F-250-Owner]

when you engage it does the transfer case lock? you can check the vaccum pump on the passenger side fender well.... also sometimes you may need to pull the vaccum line off at the hub itself and trim about a half inch off of it to make sure its sealing there at the hubs. good luck.....

 

[Mdub707]

The transfer case is working yes, since I can still use 4x4 if I get out and turn the hubs to "lock" manually. When the hubs themselves are in "auto" it will not work. They are both brand new hubs as well.

 

[F-250-Owner]

when you are driving and you flip the switch on the dash for the auto lock, do you feel the transfer case engage? if you do then its probably vaccum related as mine was....

 

[Lubbockguy1979]

Turn on the a/c then turn on the 4x4.. Does it go to defrost?

 

[Mdub707]

Turn on the a/c then turn on the 4x4.. Does it go to defrost?

I will check that, haven't used the AC in a while, it's still only getting up to about 50 degrees here during the day, but I will definitely check that later.

The transfer case is 100% without a doubt engaging, I can feel it engage even when the hubs are on auto, and the 4x4 doesn't work. I go out and turn the hubs manually, engage 4x4 on the dash and it works flawlessly. I figured it was vacuum related. I hate these damn vacuum hubs.

 

[Mdub707]

Turn on the a/c then turn on the 4x4.. Does it go to defrost?

Yes it does.

 

[Lubbockguy1979]

Well what I would start with is to turn the key on. Leave the engine off. Turn on the 4x4 and then go to the pass side fender and see if you can follow the vaccum lines to the hubs. could be just a bad hose.

 

[Mdub707]

Well what I would start with is to turn the key on. Leave the engine off. Turn on the 4x4 and then go to the pass side fender and see if you can follow the vaccum lines to the hubs. could be just a bad hose.

Ok I will try this in the morning. Seems simple enough. It amazes me that the dealer replaced both hubs and extras and didn't even fix anything... what a waste of money on their part and a waste of time on both of our parts. Thanks for the info, I'll check tomorrow.

 

[TylerDurden]

Ok I will try this in the morning. Seems simple enough. It amazes me that the dealer replaced both hubs and extras and didn't even fix anything... what a waste of money on their part and a waste of time on both of our parts. Thanks for the info, I'll check tomorrow.

Sorry you are having trouble, but at least the actual working parts are new now and you didnt have to pay for them. These trucks have their share of vacuum related maladies. I would have said that more carefully but my worktruck slips into 'defrost' mode once a year or maybe every two and everybody goes "ooops Fords got a vacuum leak again!" My personal truck is doing it now too. We've got two at work and I know they both have had problems. Oh well, there are worse things to go wrong.

 

[Mdub707]

Sorry you are having trouble, but at least the actual working parts are new now and you didnt have to pay for them. These trucks have their share of vacuum related maladies. I would have said that more carefully but my worktruck slips into 'defrost' mode once a year or maybe every two and everybody goes "ooops Fords got a vacuum leak again!" My personal truck is doing it now too. We've got two at work and I know they both have had problems. Oh well, there are worse things to go wrong.

I'm not complaining. I'm sure if I brought it back they'd fix it (or try to fix it again), just kind of amazes me with all the talk about Ford cutting down on warranty work, that they warrantied this and never resolved the issue. There is no way they test drove it after they replaced this stuff, because I knew within 10 seconds of getting into the truck it wasn't working. I didn't even have to leave the parking lot.ointlaugh:

 

[Mdub707]

Ok I turned the key forward and engaged the 4x4. The little "vacuum pump" is running and functioning from what I can tell. I followed the lines and I don't see anything visibly wrong...? Is there certain areas that are more prone to failure than others?

 

[co04cobra]

If you have vaccum at your hubs have someone turn it in 4x4 while you pull the hose of each side and check. If you have it to both sides all your lines are proabably good. And if the yellow oring on the hubs are good and since the hubs are new it probably is. The last thing to check is the big seal on the axle itself. You could tell which side is bad by plugging the vaccum hose at the hub one at a time and then seeing if the other side engages or if it doesnt go to defrost with one side plugged. Whichever one you plug makes the other side work then the plugged side needs the seal. But it is possible both sides may need it. If you plug both sides and then switch to 4x4 and it doesnt go to defrost then both sides may need it.

 

[F-250-Owner]

its prolly the pump... mine did the same thing, i used a caulking tube tip to block the side that controls the vents inside the truck for almost a year.... the pump is like 100 bucks, it takes about 2 seconds to change it out.

 

[Mdub707]

its prolly the pump... mine did the same thing, i used a caulking tube tip to block the side that controls the vents inside the truck for almost a year.... the pump is like 100 bucks, it takes about 2 seconds to change it out.

I was thinking of just swapping the pump on my buddies truck with mine since the lines look OK and that would be quick. Thanks for the idea!

 

[Rickl]

I;ve got an 04 F350 that will not go into 4x4. I checked all the fuses, they were fine. I replaced the switch on the dash,still didn't engage. I replaced the vaccum switch solinoid on the passenger wheel well. Still won't engage. My pump works fine, my blower does not go to defrost when I shift to 4x4, and my 4x4 light does not come on on the dash left side. What am I missing?

 

[Rickl]

Also took out both factory auto hubs and disassembled and cleaned and greased and re-installed. Is there a relay I'm missing?

 

[IIvonnyII]

Check your axle seals, if they aren't seated properly the 4x4 will not engage