Ford 4x4 question: LOCKED or AUTO ?

[mjw357]

'16 F-350. As far as what position to put the front hubs in. What's the difference? might seem a stupid question to some, but the owners manual does a poor job of explaining :reading: . Primarily on-road hauling or towing with occasional trips across soft/muddy fields. So it's in 4x2 99% of the time. Truck has selector knob on the dash (4x2>4x4H>4x4L). Can someone explain how this works?

 

[k0ua]

'16 F-350. What's the difference? might seem a stupid question to some, but the owners manual does a poor job of explaining :reading: . Primarily on-road hauling or towing with occasional trips across soft/muddy fields. So it's in 4x2 99% of the time. Truck has selector knob on the dash (4x2>4x4H>4x4L). Can someone explain how this works?

Not being a Ford owner for some time, and a current Chevy 4x4 owner, take this for what it is worth.

Generally 4x4 means the front drivetrain is locked into 4x4 all the time. In other words power is being fed thru the front propeller shaft from the transfer case. Auto on the other hand means that power has the ability to be fed to the front driveline but it is based on some circumstances. The transfer case in auto is using a fluid coupling not directly connected. The truck is monitoring for wheel spin on the rear driveline, and if it is encountered more power is fed from the fluid coupled transfer case into the front driveline to power the front wheels. When there is no difference in the speeds of the front and rear wheels power can then be applied to a greater extant to the rear and a lesser extent to the front.

One use for this is "patchy" snow/ice conditions on an otherwise wet or even dry road. You would not want to run in 4x4 due to tire/driveline wear, but in stop and go conditions, you may be parked on a slippery intersection and need to get going. The Auto feature will give you the traction you need to get moving and then will back off of the driveline power supplied to the front to save on wear and tear of the front driveline/tires when it is not needed in the areas that traction is good.

I assume the Ford works is some similar fashion

 

[k0ua]

Also with your transfer case in Auto, you will be able to make turns on dry pavement somewhat easier without the "torque windup" and tire "skipping" you can encounter when trying to make a turn with locked 4x4. So in summation if road conditions are uniformly slippery, use 4x4 locked for greatest traction without the delay of the truck determining you need to throw more power to the front driveline. If road conditions are variable, slippery and wet to dry and everywhere in between, use Auto to reduce driveline and tire wear. If road conditions are good use 4x2. The 4x4 locked LOW range will give a 2:1 gear reduction to all axles for additional torque in 4 wheel drive and 1/2 the speed. Used for crawling around when additional torque is required.

Actual Ford owners, if I messed this up, please comment.

 

[mjw357]

thanks for the reply, K0UA. I forgot to mention, the question regarding LOCKED or AUTO is regarding the front hubs. My previous truck (Nissan) was 4x4 but I never had to deal with changing anything other than shifting it into 4x4.

 

[k0ua]

thanks for the reply, K0UA. I forgot to mention, the question regarding LOCKED or AUTO is regarding the front hubs. My previous truck (Nissan) was 4x4 but I never had to deal with changing anything other than shifting it into 4x4.

So just to be clear you don't have an Auto position of the transfer case then? (like Chevy has had for many years)

 

[mjw357]

So just to be clear you don't have an Auto position of the transfer case then? (like Chevy has had for many years)

That's correct, there is no AUTO position on the 4x2/4x4 selector inside.

 

[Cord]

The auto position uses the ABS sensors to detect wheel slippage before engaging the transfer case. This portion is "Automatic", but it's not instantaneous. It does take a fair amount of slippage for it to engage the TC and even then the differential wheel speed needs to be acceptable for the transfer case to engage. 4wd manually shifts the transfer case to engage the front axle. Personally, the auto position is more for the people that don't anticipate the need before engaging the 4wd or forget to disengage it before returning to dry pavement.

 

[JMER817]

You have manual locking hubs. You must have the Hubs in the locked position and then you can move the 4 wheel drive shifter (or switch) inside the vehicle to 4 wheel drive. If you do not have the hubs locked in then you will not have 4 wheel drive regardless of where the shifter is set to. When running around in 2 wheel drive and you know you won't be needing 4 wheel drive unlock the hubs to save on front drivetrain wear.

 

[dieselcrawler]

The Ford hubs are vacuum operated in the 'auto' setting, and locked in all the time in the 'lock' setting. With a knob on the dash, when switched to 4x, it sends a vacuum pulse to the hub to lock it when in 'auto', another pulse to unlock when switched back to 2x. If in 'lock' setting, you will still be in 2x until late you switch it on the dash knob, but the front axle parts and drive shafts will be turning, locked into the wheels.

As long as the vacuum system works properly (wife's Excursion does not, have to manually lock hubs), 'auto' setting will likely be fine for you...

 

[k0ua]

If the selector switch on the dash does not have an Auto setting, where is this Auto setting?