How does AUTO 4WD work/what does it do?

Machria

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Can anybody explain what the AUTO 4WD does? Does it make the truck perform like an AWD (all wheel drive) vehicle like a Audio for example where there is always power to all 4 wheels, BUT they are not "locked" like in regular 4wd offroad? OR, does it only "kick in" when one of the wheels is slipping ofr something?

Lastly, can it be left on all the time, or should it only be used in bad weather/roads?

Thanks...
 

1quick1

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Auto is 2wd until it detects slippage and then it locks the front wheels as well. I believe it then goes back to 2wd when normal. This one you can leave on all the time. 4wd lock is what you want to use when it's snowy/icy/muddy and the wheels are able to slip.
 

mohemipar

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The 1/2 tons with Auto mode have the Borg Warner 44-44 transfer case which is engaged by clutch packs. There are some threads out there with hundreds of pages worth to read through on how this operates. Basically in Auto mode the truck is 2WD until a slippage is detected as said above. Once the slippage has been corrected, back to 2WD you go.

Be advised, 4WD "Lock" mode does not actually keep you in 4WD. Again, the truck will only engage 4WD when it detects loss of traction. There is a mix of reports out there saying the truck will disegnage 4WD until you come to a complete stop, or some say it will disengage when you release the gas pedal. But there is no true constant 4WD available on the 44-44 case.
 

6.7CumminsDrvr

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I’ll add one note........Power will be sent to the front wheels when A) slippage is detected and B) you are applying power.

If you are idling and your rear tires are spinning, the tcase will not engage the front axle until you step on the throttle.

This experiment is easy to try with the deep 1st gear of the 8 speed, especially in 4Lo. Find a slick spot like wet grass, ice, or really loose or soft sand...........
 

Machria

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The 1/2 tons with Auto mode have the Borg Warner 44-44 transfer case which is engaged by clutch packs. There are some threads out there with hundreds of pages worth to read through on how this operates. Basically in Auto mode the truck is 2WD until a slippage is detected as said above. Once the slippage has been corrected, back to 2WD you go.

Be advised, 4WD "Lock" mode does not actually keep you in 4WD. Again, the truck will only engage 4WD when it detects loss of traction. There is a mix of reports out there saying the truck will disegnage 4WD until you come to a complete stop, or some say it will disengage when you release the gas pedal. But there is no true constant 4WD available on the 44-44 case.

Seriously? If I put the truck in 4WD LOW, your saying it is NOT locked in 4WD full time???
 

mohemipar

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Not to say it doesn’t do its job.


44-45 is where you will see full time lock. This is on select ½ tons, ie certain Tradesman’s I believe and the Rebel. All heavy duty trucks also get it.
 

ColdCase

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There is an axle connect in the front axle thats also involved. Its an electric motor driven gear spline that slides to connect or disconnect one side for better free running. It is disconnected on 2WD mode, connected in 4Lock. I don't recall off hand what happens in auto mode, could very well be disconnected until slip is detected.

So the lock position on the selector is controlling the axle connect/lock. :) ...
 
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