dumb 4wd question

jhblaze1

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I've owned a number of 4wd vehicles and all were shift on the fly. I've never owned one that had manually locking hubs.

I'm confused over how things work on a truck that has both manually locking hubs and shift on the fly 4wd.

1: Let's say I don't touch the hubs but just shift into 4hi or 4low....do the hubs just automatically lock?
2: What if I get out, lock the hubs manually but do not select 4hi or 4 low on the shift knob? is the truck now in 4 hi just because the hubs are locked? I'd assume no because the transfer case didn't shift any power up front?

so what is the point of the manual locking option?

thx
 

davidb1841

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I've owned a number of 4wd vehicles and all were shift on the fly. I've never owned one that had manually locking hubs.

I'm confused over how things work on a truck that has both manually locking hubs and shift on the fly 4wd.

1: Let's say I don't touch the hubs but just shift into 4hi or 4low....do the hubs just automatically lock?
2: What if I get out, lock the hubs manually but do not select 4hi or 4 low on the shift knob? is the truck now in 4 hi just because the hubs are locked? I'd assume no because the transfer case didn't shift any power up front?

so what is the point of the manual locking option?

thx
Very good Questions

1. Answer: They should be, their supposed to be........but that is why you can manually lock them. (Great Feature)

2. Answer: Have not a clue but do not think so.

3. Rock Taxi, do you know this one??
 

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It is shift on the fly. When the hubs are set to auto you can shift at any time, the manual lock is for if the vacuum system wasn't working. Its a little different from the old school style of locking hubs. If the hubs are locked the axle is spinning but there is no power being transferred to it since the transfer case is not engaged.
 

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You can manually lock the hubs and stay in 2 wheel drive. Just don't make sharp turns. It behaves. It behaves like its in 4 wheel drive. Its not really good for the truck. Ive had this on 8 fords in 10 years and its always always worked as designed. Never had to manually lock them but have just to check it out. It works off a vacuum system and never had a problem
 

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I've owned a number of 4wd vehicles and all were shift on the fly. I've never owned one that had manually locking hubs.

I'm confused over how things work on a truck that has both manually locking hubs and shift on the fly 4wd.

1: Let's say I don't touch the hubs but just shift into 4hi or 4low....do the hubs just automatically lock?
2: What if I get out, lock the hubs manually but do not select 4hi or 4 low on the shift knob? is the truck now in 4 hi just because the hubs are locked? I'd assume no because the transfer case didn't shift any power up front?

so what is the point of the manual locking option?

thx

If they are manually locked they are locked. If they are unlocked you can lock em up electronically. I saw one video I believe it was TFL where they locked the rears while in 2 wheel drive.

I am not 100 percent sure on this answer but pretty sure.
 

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Very good Questions

1. Answer: They should be, their supposed to be........but that is why you can manually lock them. (Great Feature)

2. Answer: Have not a clue but do not think so.

3. Rock Taxi, do you know this one??

I agree - this is a good question.

I have read the manual a couple of times, and looked at a lot of schematics, but don't have them open now.... The following is my understanding - but I am willing to listen if I have something wrong.

I am used to Warn hubs that are either free spool, or locked. The Ford hubs appear to be a different animal entirely. They are "free" in the Auto selection, unless the transfer case is engaged in 4WD. Then, they lock up to provide front traction.

As I understand it, the hubs automatically lock by one of the hoses to the knuckle when you switch to either 4H or 4L I assume a vacuum actuator locks the hub in. I have not disassembled and tested to confirm. Also, it appears you can manually select from Auto to Lock on the hub selector to ensure the hubs are locked and not rely on electronics..

I have turned both to Lock in the driveway to ensure they will rotate, but have had 100% success to date with the Auto selection setting and 4H and 4L in mud and rocks.

Ed
 

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The manual feature is a backup incase the automatic hubs do not work. My vacuum pump module failed in my 2005 F250 in the middle of a snow storm, so with out the manual option, I would not been able to engage 4wd, since the hubs are engaged by vacuum. Also, like others have said, just because you lock the hubs it does not give you 4WD until the transfer case is engaged. I always exercise my 4wd a couple times a year just to make sure it is working correctly.
 

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Good thread. I myself was curious about this. I've left mine in Auto since I bought it.
I can confirm this at least on my 2002. Was outin the back country in winter in 4WD. Got stuck and realized I was not in 4 WD. Locked my hubs and got 4WD and got unstuck. Later found a hole in the vacuum hose that caused the hubs to not lock automatically.
 

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I can confirm this at least on my 2002. Was outin the back country in winter in 4WD. Got stuck and realized I was not in 4 WD. Locked my hubs and got 4WD and got unstuck. Later found a hole in the vacuum hose that caused the hubs to not lock automatically.
When you manually lock the hubs you need to lock them on each side correct?
 

davidb1841

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I agree - this is a good question.

I have read the manual a couple of times, and looked at a lot of schematics, but don't have them open now.... The following is my understanding - but I am willing to listen if I have something wrong.

I am used to Warn hubs that are either free spool, or locked. The Ford hubs appear to be a different animal entirely. They are "free" in the Auto selection, unless the transfer case is engaged in 4WD. Then, they lock up to provide front traction.

As I understand it, the hubs automatically lock by one of the hoses to the knuckle when you switch to either 4H or 4L I assume a vacuum actuator locks the hub in. I have not disassembled and tested to confirm. Also, it appears you can manually select from Auto to Lock on the hub selector to ensure the hubs are locked and not rely on electronics..

I have turned both to Lock in the driveway to ensure they will rotate, but have had 100% success to date with the Auto selection setting and 4H and 4L in mud and rocks.

Ed
Thank You....I knew you would know this.....
 

J Money

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I can confirm this at least on my 2002. Was outin the back country in winter in 4WD. Got stuck and realized I was not in 4 WD. Locked my hubs and got 4WD and got unstuck. Later found a hole in the vacuum hose that caused the hubs to not lock automatically.
When I bought my Excursion I took it on a trip and got stuck in 4WD. Was scratching my head for a few minutes. Manually locked the hubs... Problem solved. Later on found the broken vacuum hose. I think that was a $2.00 fix but took probably 2 hours of wondering why the 4WD wasn't engaging.

AND

This happened in my 2014 FX4. Installed some A-Arms, Coil Overs and a bunch of other junk... everything was good on a shakedown drive or 20. However one day (luckily in the rain) I felt some weird feedback in the steering and some vibration. Apparently the hubs ARE LOCKED when starting the truck until they have some vacuum to release them. Again... $2.00 solution. This one was kind of mind blowing because it was the complete opposite in 2014 than 2002.

I haven't checked on the new Super Duty trucks but there were some upgrade kits for the hubs in the past... beefier auto versions or converting them to all manual.
 

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I've owned a number of 4wd vehicles and all were shift on the fly. I've never owned one that had manually locking hubs.

I'm confused over how things work on a truck that has both manually locking hubs and shift on the fly 4wd.

1: Let's say I don't touch the hubs but just shift into 4hi or 4low....do the hubs just automatically lock?
2: What if I get out, lock the hubs manually but do not select 4hi or 4 low on the shift knob? is the truck now in 4 hi just because the hubs are locked? I'd assume no because the transfer case didn't shift any power up front?

so what is the point of the manual locking option?

thx
1. Hubs are vacuum actuated. the truck free-wheels the front so the front diff is disconnected in normal driving. When you select 4hi the vacuum pump engages the front hubs automatically. The manual option is a fail safe in case of vacuum failure or if you just want peace of mind that the hubs are in fact locked in and driven
2. You can keep the hubs engaged at all times, even in 2wd. Doesn't mean they are driven. it just means that they aren't free-wheeling. No reason to do this. Adds unnecessary drag on the drivetrain
 

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The following gives a good overview:

 

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Rock Taxi said:

"I have turned both to Lock in the driveway to ensure they will rotate"

When I pick mine up at the dealership how can I tell if the autolock is working? I would think you would have to jack up the front end.
 

thevol

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I am not a fan of these auto hubs but at least they have the manual override. Have had the truck tell me the system is fully in 4wd but the hubs are not totally locked in and get a ratchet or grinding noise, especially if you are in mud and spin the back tires. Feels like its going to tear something up but they do eventually lock in, may take a revolution or two to engage, not good if you are stuck in 2wd and rear tires spinning...
 
OP
J

jhblaze1

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Rock Taxi said:

"I have turned both to Lock in the driveway to ensure they will rotate"

When I pick mine up at the dealership how can I tell if the autolock is working? I would think you would have to jack up the front end.


it's probably a rare occurrence that it doesn't work right off the lot, I'm just unlucky that way.

just take it for a test drive before finalizing deal. Make sure hubs are set to auto and then engage 4wd and take a few turns on dry pavement. You'll be able to feel it.
 

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I've always been able to tell in the dirt but at the dealer I would know that the front diff is engaged but not sure I would know the hubs are. I guess if I know the diff works then I'm good to go knowing I can always manually lock em. Getting some dirt will occur very soon after pickup, trust me.
 
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