4wd

[jljbtm]

Anyone know the difference in 4wd "auto" and 4wd "lock"?

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[Burla]

Did you try search?

 

[ss12108]

Oh man did you just open a can of worms haha...

You're going to get different answers so I'll just say this. In THEORY, Auto only engages the front tires if they detect slippage. In THEORY, lock engages all 4 tires when you have it turned on, but apparently lock also waits for some slippage.

Get ready for a lot of notifications of replies to this post OP...Good luck haha

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[WillO]

Whatever it is. It's certainly not AWD [emoji23]


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[jljbtm]

Ok haha, there's alot of opinions out here

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[cubmedic]

 

[Burla]

Page 430 of your owners manual, you can find it free online, search.

This electronically shifted transfer case provides five
mode positions:
• Two-wheel drive high range (2WD)
• Four-wheel drive automatic range (4WD AUTO)
• Four-wheel drive lock range (4WD LOCK)
• Four-wheel drive low range (4WD LOW)
• Neutral (NEUTRAL)
This electronically shifted transfer case is designed to be
driven in the two–wheel drive position (2WD) or fourwheel
drive position (4WD AUTO) for normal street and
highway conditions on dry hard surfaced roads). Driving
the vehicle in 2WD will have greater fuel economy
benefits as the front axle is not engaged in 2WD.
For variable driving conditions, the 4WD AUTO mode
can be used. In this mode, the front axle is engaged, but
the vehicle’s power is sent to the rear wheels. Four-wheel
drive will be automatically engaged when the vehicle
senses a loss of traction. Because the front axle is engaged,
this mode will result in lower fuel economy than
the 2WD mode.
When additional traction is required, the transfer case
4WD LOCK and 4WD LOW positions can be used to
maximize torque to the front driveshaft, forcing the front
and rear wheels to rotate at the same speed. This is
accomplished by rotating the 4WD Control Switch to the
desired position. Refer to “Shifting Procedure” for specific
shifting instructions. The 4WD LOCK and 4WD
LOW positions are designed for loose, slippery road
surfaces only. Driving in the 4WD LOCK and 4WD LOW
positions on dry hard surfaced roads may cause increased
tire wear and damage to the driveline components.
NOTE: The transfer case NEUTRAL position is selected
by depressing the recessed button (with a ballpoint pen
or similar object) located in the center of the 4WD Control
Switch. The transfer case NEUTRAL position is to be
used for recreational towing only. Refer to “Recreational
Towing” i

 

[clh1220]

Not again.

 

[sbarron]

The problem is everyone has a different definition of AWD, 4WD, etc

Hell, even car manufacturers, call different feature sets by different names, EVEN in the same year, depending on who they are marketing what vehicle to.

By Fiats definition, we don't have AWD, not because it can't fit the definition, but because few truck buyers want to hear the term AWD.


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[DannyMK2]

The problem is everyone has a different definition of AWD, 4WD, etc

Hell, even car manufacturers, call different feature sets by different names, EVEN in the same year, depending on who they are marketing what vehicle to.

By Fiats definition, we don't have AWD, not because it can't fit the definition, but because few truck buyers want to hear the term AWD.


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its really not that complicated. there are no different definitions. it has nothing to do with RAM not 'calling' it awd and everything to do with the way the system works. car manufactures have different names for their AWD systems because their system might function slightly different then the next company. the concept is still the same. that has nothing to do with 4x4 vs AWD. none of this has anything to do with the question at hand though.

the difference between 4x4 lock and 4x4 auto is simple. 4x4 lock engages both axles all the time. 4x4 auto only engages the front axle when slippage is detected in the rear. the only quirk to this is if your transfer case is not functioning correctly, as some have had issues with. however, considering everything is working properly thats how the system works.

 

[jschwanke84]

Really don't understand how there can possibly be so many different opinions out there on this.... There is a clear difference between 4lock and 4auto.

4lock engages front and rear all the time. 4auto only engages the front when loss of traction is detected in the rear. Simple. Period. End of story. If you think your truck isn't functioning like that when using these systems, something is probably wrong with your truck and you should have it looked like. There is no gray area here. This is how 4x4 works.

 

[sbarron]

Really don't understand how there can possibly be so many different opinions out there on this.... There is a clear difference between 4lock and 4auto.

4lock engages front and rear all the time. 4auto only engages the front when loss of traction is detected in the rear. Simple. Period. End of story. If you think your truck isn't functioning like that when using these systems, something is probably wrong with your truck and you should have it looked like. There is no gray area here. This is how 4x4 works.

You're correct, until someone throws in the AWD argument (which we don't have). That said, our "4 Auto" is close enough to another manufacturers AWD. Agreed that if people read the users manual (doubtful) and used the definitions therein, (even more doubtful), this argument would be dust in the wind.


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[Rzrman328]

In theory.....lol

 

[BJSwizzle]

I ended up picking up a whole dash piece, which came with the 4wd shifter, my stock one doesn’t have this option, does anyone know if I switched it out, would it work?

 

[gofishn]

I ended up picking up a whole dash piece, which came with the 4wd shifter, my stock one doesn’t have this option, does anyone know if I switched it out, would it work?

No.
4Auto has a 44-44 transfer case.
Non 4Auto has a 44-45 transfer case.
Most feel the 44-45 is a better transfer case when 4 wheel drive is actually needed.

 

[BJSwizzle]

Cool, thanks for the heads up!

 

[crash68]

Really don't understand how there can possibly be so many different opinions out there on this.... There is a clear difference between 4lock and 4auto.

4lock engages front and rear all the time. 4auto only engages the front when loss of traction is detected in the rear. Simple. Period. End of story. If you think your truck isn't functioning like that when using these systems, something is probably wrong with your truck and you should have it looked like. There is no gray area here. This is how 4x4 works.

Unfortunately even in "4X4 Lock" with the BW44-44 full time transfer case(has Auto button), there is no clutch engagement or power transfer to the from wheels with no or minimal throttle. Here is a post on the subject: https://www.ramforum.com/threads/transfercase-diagram.55161/page-4#post-1920647
It's the BW44-45 part time transfer case(no Auto button) that engages the front wheels all the time.
With the two different transfer cases and people not familiar how the two differ, that's how you get the difference in opinions. Probably a lot of people think the BW44-44 is how 4X4 is supposed to work, it should be described as All-Wheel drive(but that doesn't sell as well).

 

[Ken226]

Definitions and functions vary, depending on who is doing the defining, and depending on the transfer case model.

With regards to our 4th gen rams though, ill assume your talking about the borg warner 44-44.

I've been through it completely. My 44-44 has been replaced with a 44-45, and is sitting in a box in my garden shed. Ive had my bw44-44 stripped apart, every assembly reduced to its constituent components.

I don't bother with definitions as they tend to be subjective, but i can tell you whats inside the 44-44 and how it works.

All of the torque, in all modes (auto, lock and low) is transferred through a ball-ramp actuated clutch. There is no classical splined/meshed lockup.

In 4 auto, when wheelspeed sensors detect the loss of rear wheel traction, the computer powers a friction producing rotor/stator set inside the transfer case, which creates a small amount of clutch engagement. This internal clutch plate friction (from the rotor/stator) allows the engine to -wind up- the ball ramp actuator to compress the clutch plates together and transfer torque to the front. (The ball ramp actuator has 3 balls, in 3 raceways. The windup takes about 120° of ballramp rotation x the gear ratio. The ballramp converts twisting force into compressive force, so basically, the more engine power you apply, the harder the clutch plates are forced together. If you reduce engine power, the clutch plate compressive forces are proportionally relaxed. After rear wheel traction is regained, the computer shuts off power to the rotor/stator set.

The wire that carries current to the stator/rotor is something like 18awg, so it can't even nearly supply enough current to fully close the clutch. It just starts the process and engine power does the rest. Its even possible that in normal 4 lock operation, the computer only temporarily powers this circuit to start the clutch engagement process, rather than keeping it powered. I was never brave enough to measure the current while someone was on the gas. I got measurable current, a few amps, while under the truck, up on jackstands in gear, 4 lock and idling with the wheels turning (i know, unsafe).

I did try putting an inductive pickup around the wire, routing it to my multimeter in the cab and driving on ice te check the voltage, but my inductive pickup wont measure a low voltage field from a dc circuit.

In 4 lock and 4 low modes, the electrical signal to the rotor/stator is supposed to be constant, assuming the trucks in drive and 4 lock selected, (i measured some current while under the truck, noone touching the throttle in 4 lock) so there is always a small (very) amount of force squeezing the clutch plates together. So, in this case (4 lock and 4 low), any time the rear wheels slip, the ballramp will force the clutch plates into compression. Any time the front wheels try to spin faster than the rear wheels, such as in a tight turn, the ballramp unwinds and the clutch plates release. (The ball ramp raceways are bi-directional, so when switching into reverse, there is more delay as the ball ramp unwinds, then winds up in the opposite direction). (Forgive the term "winds up", i couldnt think of a more descriptive one)

But, in all modes, power is transferred through a ballramp actuator and clutch.

When not actually in use, oil will get between the individual clutch plates. So, when you first activate 4wd modes, there may be some delay in front wheel engagement as the clutch plates are compressed and oil is squeezed out.

Also, due to the nature of a ballramp actuator, as the axial forces which put the clutch plates in compression are dependent on the torsional friction between the plates, worn or damaged clutch plates result in slower engagement and even more heat/wear. They really need to be kept in good shape to work well.

For guys who like and want too keep 4 auto, Rockland Gear makes a significantly stronger clutch plate pack that is a significant improvement in performance.


Heres an example of how a ball-ramp actuator works:

Except, in the case of the bw44-44, the computer doesnt engage the ball ramp. The computer engages the stator/rotor, which then uses engine torque to engage the ball ramp. A reduction in engine torque, relaxes the ball ramp.

My concern, and the reason i switched to a 44-45, is due to the 44-44s behavior on surfaces like soft sand, when the traction control starts braking wheels and reducing power. This can result in fluctuating ballramp and clutch engagement, lots of friction and heat, and premature wear.

In situations like this, the best option with a 44-44 would probably be to turn off the traction control and stay on the gas.

 

[WilliamS]

I wish the owners manual was correct, as 4lock does anything but in our trucks, 4 lock and 4 low will not fully lock without some traction loss or heavy input on the skinny pedal. 4auto has always kept me out of trouble on roads and ramps, but off road it can leave a little to be expected of a 4wd. That all being said, I havent been stuck in the 5 years of Ram ownership been off road plenty.

Tires and Knowledge are the keys to success.

 

[chrisbh17]

I had a short chance to use my 44-44 in 4-Auto without traction control engaged. There is a ramp to a parking garage where I work, the ramp itself was not plowed and had about 1" of snow on it. The lane you drive on to turn onto the ramp WAS clear. So I attempted to back up the ramp a few times.

I started off in 4-Auto on purpose (in case the snow cleared off from fishtailing in 2WD). Engaged 4-Auto while the front wheels were on clear pavement and the rears were going up the ramp. Didnt HAMMER the throttle, but did give it enough that I knew it should break traction. With traction control off, the fronts pushed the truck up the ramp no problem. Maybe a slight delay in engagement but overall did quite well.

As a control, I rolled back down the ramp, put the truck back in 2WD and attempted the same test. Truck got about 1 foot up the ramp before it started fishtailing and traction control kicked in.

Overall I am happy in this specific case. I think the key to living with the 44-44 is to disable traction control (which, apparently, can be done in any 4WD mode). Just hold the traction control off button for about 10 seconds and the EVIC will say when it is disabled.