Auto locking hubs

MPTxTremor

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Can someone explain the auto locking hubs to me? I’d rather it be unlocked and locked the auto lock gives me anxiety that I’m unknowingly locking them by mistake or something.
 

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In auto they are engaged by pulling vacuum on the top tubes. This causes the black diaphragm to shrink engaging the teeth with the splines of the axle shaft.

Locking the hubs over rides this by manually pushing the diaphragm into the locked position .
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Jrod250

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Lock is locked. Auto is unlocked until you engage 4wd then a vacuum locks them automatically

from my understanding IF you know you’ll probably NEED 4wd unexpectedly, then just LOCK them. If your in 2wd and get stuck there is a small chance your auto may not engage.
Correct me if I’m wrong
 

ccw

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If your in 2wd and get stuck there is a small chance your auto may not engage.
Yes? But the reasoning is auto lock can take a partial rotation before it actually locks in. If you’re stuck and can’t move enough, the hubs will never engage.

There is a small risk that the hubs won’t lock because of a mechanical issue, but that’s not the usual issue.

On the other hand, the manual override is always available so it’s not the end of the world if they won’t engage automatically. Just get out and engage them manually. Would suck if you’re in nasty conditions and may not want to walk outside in that moment, though (think mud pit).
 

Sccritterkiller

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Can someone explain the auto locking hubs to me? I’d rather it be unlocked and locked the auto lock gives me anxiety that I’m unknowingly locking them by mistake or something.
Running them locked and not in 4wd won't hurt anything but MPG. They actually make IWEs without the vacuum for models without lockout hubs...if you have ever dealt with IWE/vacuum issues you know why. Spent 2 hrs replacing all vacuum line on my Expy on Sun. Apparently the rubber vacuum line connections are good for about 10yrs...after that they just crumble and you loose vacuum and it tries to shift in 4wd at hwy speeds...makes an awesome grinding sound...lol
 

jhblaze1

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my auto locking hubs were broken upon delivery. I got stuck in the mud and had to winch out because I didn't even know I had the option to manually lock them (every 4x4 I've ever owned ONLY had auto lockers or Jeep style where it's actually like an axle sleeve type thing/front axle disconnect).

Ford's auto locking hubs are cheap trash, have been forever, and Ford doesn't care to fix it. Warranty fixed my issue, but going foward I'll never trust them and will manually lock if I know I'm going offroad or going to drive in snow.
 

Jrod250

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my auto locking hubs were broken upon delivery. I got stuck in the mud and had to winch out because I didn't even know I had the option to manually lock them (every 4x4 I've ever owned ONLY had auto lockers or Jeep style where it's actually like an axle sleeve type thing/front axle disconnect).

Ford's auto locking hubs are cheap trash, have been forever, and Ford doesn't care to fix it. Warranty fixed my issue, but going foward I'll never trust them and will manually lock if I know I'm going offroad or going to drive in snow.
I think I remember you telling that story here. lol
 

Grabber

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If you are doing serious off roading, then I would lock them. The auto hubs will work fine otherwise. The manual option is a nice backup, it saved me in a middle of a snow storm, when the vacuum pump module that controls the hubs in my 2005 went bad. If there was not a back up, I would have been screwed. I also put my truck in 4wd about once a month just to keep everything working. Just make sure you are operating it when you are not turning as the 4wd system is not engineered for dry pavement (Needs slip) Also, there are a zerk fitting on each of the universal joints in the steering knuckle on the front axle. Make sure you hit it with some grease once a year, especially if you are using your 4 wheel drive a lot.
 

DanMan583

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There is a better option for those who are so inclined.
I’m thinking about getting a set of these as soon as I am out of my warranty.

 

Cococounty

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Can someone explain the auto locking hubs to me? I’d rather it be unlocked and locked the auto lock gives me anxiety that I’m unknowingly locking them by mistake or something.
I always run mine in AUTO and if I get in a bad situation turn it to four high or low and they auto kick in you don’t have to worry about them being in auto position they will not be engaged until you select four high or four Lo and You need to be at a stop to engage them they will not accidentally lock The only time I would lock them is if I was in snow or mud all day every day so far they have worked great for me
 

surfscottydog

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Can someone explain the auto locking hubs to me? I’d rather it be unlocked and locked the auto lock gives me anxiety that I’m unknowingly locking them by mistake or something.
In my work truck I always keep my hubs locked. The truck doesn’t have an auto feature and I don’t mind the gas mileage
 

Briski

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If you want to know that they are locked, then manually lock them. It’s better to know then get stuck!
 
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qpayne1989

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2wd with hubs in auto: the front wheels are disconnected from the front axle and front driveshaft is disconnected from the transfer case. Driveshaft and front axle shafts just sit there while driving without spinning saving on mpg and wear.

2wd with hubs in lock: the wheels are locked to the front axle shafts causing axle, differential and driveshaft to spin with the wheels as you go down the road. However it is still disconnected at the transfer case so it does not transfer any engine torque to the front wheels.

4x4 with hubs in auto: vacuum is applied to the hub lock locking the wheels to the front axle shafts. At the same time the transfer case locks to the front driveshaft to transfer engine torque to the front wheels.

4x4 with hubs in lock: If there is a fault in the auto lock vacuum system Ford made it so that system can be bypassed manually to lock the wheels to the axles. This is much more reliable and pretty much guarantees they will be locked. I would not drive like this all the time because it will wear out those components faster (seals etc.) Only when in 4x4

If the hubs don’t lock in one way or another on BOTH sides your 4x4 will not work. All the torque will follow the path of least resistance spinning an axle that is not connected to a wheel. If you are stuck in 4x4 and at least one wheel is spinning in the front your 4x4 is working perfectly. If neither front wheel is spinning the 4x4 is not working. A locking differential is the only way to guarantee both wheels spin on an axle whether it be selectable like the rear differential on a tremor or automatic like some Chevys have. Id say selectable is better if you know to lock it before an obstacle.

A limited slip like the tremor front differential guarantees both wheels spin until there is about 50ft lbs or so torque difference between the wheels they then break free from each other. Helpful hint: riding the brakes a little while still on the gas in a tough situation can help keep a limited slip locked up longer especially on a front axle. This is because it helps even out the drag on each front wheel keeping the differential away from that 50ft lb break away torque. Sounds stupid to ride your brakes but I’ve seen it proven true.

An open differential like the front ones on non tremor super duties can only guarantee one of the two wheel will spin.

I hope this helps and isn’t just an info overload.😂
 

qpayne1989

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To better answer what you asked the only way you can accidentally lock the hubs in auto is if you turn the 4x4 switch from 2h to 4h somehow without knowing. I can’t remember what the max speed is to shift to 4x4 high but I’d keep it under 40 or so. If this happens at say 75mph down a freeway the transfer case might just blow to pieces.😳 I doubt the control modules would even let that happen though. Ford doesn’t like stuff blowing up when it’s under warranty because it can be difficult for to prove how it happened. Just don’t bump the switch.😂😂😂
 

ccw

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I can’t remember what the max speed is to shift to 4x4 high but I’d keep it under 40 or so. If this happens at say 75mph down a freeway the transfer case might just blow to pieces.😳
Interestingly, the owners manual doesn’t mention a maximum speed for shifting into or out of 4H. Personally I would be comfortable doing it up to 60mph - that’s what I’ve done in my F-150 for years without issue - but be sure to let off the gas when shifting to reduce load on the drivetrain.

Of course, slower is better in this case. You won’t do any damage by shifting at a slower speed. :)

Here’s the relevant page in the owners manual: https://www.fordservicecontent.com/...&userMarket=USA&div=f&vFilteringEnabled=False
 

qpayne1989

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Interestingly, the owners manual doesn’t mention a maximum speed for shifting into or out of 4H. Personally I would be comfortable doing it up to 60mph - that’s what I’ve done in my F-150 for years without issue - but be sure to let off the gas when shifting to reduce load on the drivetrain.

Of course, slower is better in this case. You won’t do any damage by shifting at a slower speed. :)

Here’s the relevant page in the owners manual: https://www.fordservicecontent.com/...&userMarket=USA&div=f&vFilteringEnabled=False
I read something like 55 on some vehicle somewhere. But that may have just been on my 97 Nissan hardbody 😂 If it doesn’t have one it probably isn’t important. Any slight turn of the wheel or tiny size variation in the wheels puts a lot of strain on something somewhere in the drivetrain at higher speeds when the t case is locked up. Most likely tires to ground will be the weak link which is fine. When turning all four wheels are spinning at different speeds. Also the average of the front two wheels is different than the average of the back two. If on a high speed turn on dry pavement you suddenly slam two driveshafts spinning at different speeds together the weak link could be that aluminum transfer case housing. Also even moving straight keep in mind that the front driveshaft isn’t moving at all until it is put into 4x4. If the t case locks before the hubs and a driveshaft moving at 0rpm instantly has to spin at the same speed as the rear driveshaft at the mercy of a 7000 lb truck going 75mph down the road it might be pretty hard on the t case. I’ve replaced a couple transfer cases under warranty that mysteriously exploded. One was on a raptor that Im pretty sure they jumped it with the accelerator hammered when the rear wheels hit first it blew up. 😂 They said they where just cruising down the road and it just blew up so who knows. If we have no way to prove it we’ll just warranty it. I definitely agree the slower the better. The transfer cases in these things are pretty tough. I hope I didn’t scare anyone in saying that. This is all hypothetical. Very unlikely that it could ever happen even if on accident
 

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A limited slip like the tremor front differential guarantees both wheels spin until there is about 50ft lbs or so torque difference between the wheels they then break free from each other. Helpful hint: riding the brakes a little while still on the gas in a tough situation can help keep a limited slip locked up longer especially on a front axle. This is because it helps even out the drag on each front wheel keeping the differential away from that 50ft lb break away torque. Sounds stupid to ride your brakes but I’ve seen it proven true.
Bad way to say it, the limited slip is a torque multiplier in order for it to work the lower traction wheel must have enough torque that can be multiplied to turn the opposing wheel. It doesn't have a high break point where it wont work but a low point where it cannot engage. This is why applying the brakes will add artificial traction to get the opposite wheel spinning.
 

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DanMan583

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I wonder if that fits a 2020 Tremor?
I’m pretty sure this model does. That’s why I posted it.
A quick call to Warn to confirm probably wouldn’t hurt though.

I do plan on getting these once I’m outside of the warranty timeframe.
I also plan on upgrading my battery too, but that’s a different discussion.
 

VB!

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I have a long steep driveway that is 4x4 only if backing up it or if its raining. The auto hubs are a great for this as I don't have to get out just to get the truck from the street to the house. I did find that I have to be careful when I turn the switch back to 2WD. If I do it without driving up a straight part a bit the hub disengagement is rather violent.

In real 4x4 situations I just lock the hubs before I get to the point of needing 4x4.
 

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