2 or Auto

[Knotsure]

Look. All these technical points are reading to much into it. I know from personal experience with my auto 4 that it acts more like an awd than 4x4 when combined with traction control and stabilitrac. These systems all act together and it is nothing like a full 4x4 when switched to auto. It may not give power to each wheel but the op is asking if the auto 4 is more like awd or more like 4x4. The answer to that is it is more like awd than 4x4. You can turn it on and not worry what speed or what surface you are driving on. There is no wheel hop and you can't spin all 4 tires at once. More like awd than 4x4. Seems clear to me.

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 leveled front end

[Donstar]

Look. All these technical points are reading to much into it. I know from personal experience with my auto 4 that it acts more like an awd than 4x4 when combined with traction control and stabilitrac. These systems all act together and it is nothing like a full 4x4 when switched to auto. It may not give power to each wheel but the op is asking if the auto 4 is more like awd or more like 4x4. The answer to that is it is more like awd than 4x4. You can turn it on and not worry what speed or what surface you are driving on. There is no wheel hop and you can't spin all 4 tires at once. More like awd than 4x4. Seems clear to me.

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 leveled front end

To me, AWD is an acronym like FWD and RWD. When I see a vehicle with an AWD badge, I expect all wheels are powered at all times. 4X4 indicates, to me, there is driver choice. This isn't technical but I don't see the terms as close to being interchangeable.

[Silverado Steve]

Yes, plus as i said several pages back, to the casual truck owner sure, you can equate 4auto to AWD, the thing is we are on a site where people exchange knowledge and we have a good chunk of gearheads here too. Saying 4auto is the same as AWD is misleading. Would you want your mechanic telling you your cenrer differential was burnt out and it needed replacing now or your truck would not be able to be driven in 4wd, when all you neede was a new electronic switch? How about your front diff needed new clutch plates because you would screw up your truck if you ever turned the wheels in 4wd again? Minor details but again, how do you think people get conned into headlight oul, blinker fluid or veing charged for 8 sparkplugs in a honda civic?

[SouthernSilveradoGuy85]

 

[j3st3r]

Don't you think if it was exactly like AWD they would just call it AWD and not 4 auto? I mean that's a simple thing too realize. There are many differences and you even said it's only similar which you're trying to make the word "similar" sound like the word "exactly".

Definitely not here to argue the point about AWD and 4WD because these are clearly not an AWD vehicle, but on the DIC when it's in auto mode it says AWD not 4WD. It doesn't change to 4WD on the DIC until you change it to 4hi or 4low. Could be why there is so much confusion.

[Knotsure]

We are on an enthusiast forum, yes that is right. However, The point of this post is to determine if auto 4 is ok the drive on dry pavement and at what speed is it safe. In that regard auto 4 is closer to awd than 4x4 when combined with the traction control systems, because you can drive it on any surface at any speed. That is the answer to the post but not the answer to the larger question of awd vs 4x4/auto 4. All this info is being repeated and repeated and has been on other posts as well. I am sure the OP has his answer. Enjoy brother. And Go Cowboys!!!!

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 level

[Jon A]

 

Once slippage is detected (difference in speed from the front prop shaft to the rear prop shaft) the encoder motor locks the clutch pack in fully and at that point the transfer case is fully locked with equal split in power.

 

 

But that's not how it works. Zero literature on the subject agrees with the above statement. If fully locked the same binding/crow hopping issues that occur in 4Hi would occur and the system would be of little value on paved roads.

 

From the theory of operation from GM in a bulletin when it was upgraded:

 

 

 

The New Venture Gear model NVG 246 RPO NP8 transfer case is a two speed automatic, active, transfer case.....

 

The Auto 4WD position allows the capability of an active transfer case, which provides the benefits of on-demand torque biasing wet clutch and easy vehicle tuning through software calibrations. The software calibrations allow more features such as flexible adapt ready position and clutch preload torque levels. The technology allows for vehicle speed dependent clutch torque levels to enhance the performance of the system. For example, the system is calibrated to provide 0-5 ft lb of clutch torque during low speed, low engine torque operation, and predetermined higher torque for 40 km/h (25 mph) and greater. This prevents crow-hop and binding at low speeds and provides higher torque biases at higher vehicle speeds, in order to enhance stability......

 

In the Auto 4WD mode, the transfer case shift control module monitors rear wheel slip speed, based on the inputs from both the front and rear propshaft speed sensors. When the vehicle experiences a rear wheel slip condition, the transfer case shift control module sends a pulse width modulated (PWM) signal to an electronic motor, which is the transfer case encoder motor. This motor rotates the transfer case control actuator lever shaft, applying a clutch pack. This clutch pack is designed to deliver a variable amount of torque, normally delivered to the rear wheels, and transfers it to the front wheels. Torque is ramped up to the front wheels until the front propshaft speed sensor matches that of the rear propshaft speed sensor. Torque is ramped down to the front wheels. The process would repeat if rear wheel slip is detected again.....

 

During the Auto 4WD mode, the power flow is the same as it is in the 4HI mode. Except, during the Auto 4WD mode, the encoder motor (15) rotates the control actuator shaft lever (14) to the correct torque level positions. Rotating the control actuator (14) to the various positions changes the clutch torque level. When a difference of front propshaft (13) to rear propshaft (10) speed is recognized, the transfer case control modules command for more, or less clutch torque.....

 

You had mentioned NP and that information applies to the NVG 246. Of course we no longer use that as it has been replaced by the MP 3023/24 which do have internal differences but the theory of operation is much the same:

 

 

 

In the Auto 4WD mode, the unit will engage an internal wet clutch to bias torque from the rear wheels to the front wheels automatically with no driver involvement. The computer software program is tunable to provide more-advanced features that make the clutch response time extremely quick and create the proper torque load on the internal clutch without creating the driveline windup that causes crow hop and other NVH concerns at low speeds. The computer receives wheel-speed signals from all four wheels and interprets a difference between front- and rear-wheel speeds as a slip. This engages the transfer-case actuator (motor) to apply the internal clutch to send power to the front wheels until the wheel speeds equalize, and then the electronics will release the internal-clutch pressure to return power to the rear wheels.....

 

-----Transmission Digest, March 2013

 

 

 

The transfer case motor is a permanent magnet, PWM, bidirectional unit, currently manufactured by Bosch (Daewoo on 2011 applications; figure 5). The TCCM controls the drivers for the motor A and motor B circuits. The motor current varies depending on the command, and to meet the clutch slip requirements in Auto Mode...

 

....As the actuator cam rotates, the balls located between the levers are forced up the ramps built into the levers. This forces the levers to move apart, applying pressure to the clutch. Increasing the clutch apply pressure reduces clutch slip, which, in turn, increases the torque applied to the front driveshaft (figures 6 and 7).

 

----Gears May/June 2011

[Jon A]

Saying 4auto is the same as AWD is misleading.

 

Saying AWD is the same as AWD is misleading. There are dozens upon dozens of different configurations which have had that label slapped on them. Arguing one thing is and another isn't is an argument of semantics. Arguing the Auto Mode these trucks have isn't even similar to some AWD systems is stretching the semantics to the point of being misleading. Especially since GM themselves have actually called this system AWD in the past.

 

You may remember the Trailblazers/Envoys of 2002-2007 or so. They used the NVG 226 transfer case which was of the same family and had the same operation as the 246 described above (same option code).

 

There were two lesser known twins built on that platform--the Olds Bravada and the Buick Ranier. They used the NVG 126 transfer case which was the same as the 226 but lacking a low range (one speed gearbox). Otherwise they were the same. These vehicles used a solid gear in place of the splined front disconnect on the front right halfshaft, force the front wheels to be connected through the differential all the time. These vehicles lacked a 4WD selector but were instead operating in "auto mode" all the time.

 

Their operation was identical to that of a Trailblazer in Auto Mode (save for differences in the tuning of the VARIABLE torque application) all the time.

 

GM labeled these vehicles as AWD with their "SmartTrak" system. You may argue semantics and say they weren't a "true" AWD system, or say it was a pretty lousy system as AWD goes (which I agree with), but the fact GM themselves labeled this type of system as an AWD system makes it pretty difficult to argue it's not even similar to any AWD system.

[SouthernSilveradoGuy85]

Not talking about the actual mechanics of any of these systems. The simple fact is that AWD is full time and can't be turned off while 4 auto can be turned off and it's not active 100% of the time even when on. I'm not sure if the fact is in deed a fact that with 4 auto on that the power split is 10/90 unless slippage is detected, but even so it's either 10/90 or 50/50, no in between. Even if they had a 4x4 system that works exactly like an AWD system if put in 4 auto, it still isn't AWD since it's not full time and can be turned on and off. It's that simple. Oh and 4x4 you have the option of a 4LO gearing while AWD doesn't.

 

Also the reason I think it says AWD on the DIC is between it's easier to just put AWD since it's 3 letters and numbers as 4x4, 2 hi, 4hi and 4lo that to try to fit 4 auto/auto 4. Just how I figure, could be completely wrong though. If it was just like an AWD system don't you think they would just put AWD on the knob instead of Auto? Hell as tight as manufacturers are when penny pinching, it would have been cheaper to have 3 letters instead of 4.

[Jon A]

but even so it's either 10/90 or 50/50, no in between.

 

False. Please read above.

[kstruckcountry]

Variable: able to be changed or adapted.

 

Sent from my SM-G920V using Tapatalk

[Knotsure]

Your not going to be able to convince southernsilveradoguy. He has his mind made up and will argue his opinion to the death. I promise.

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 level

[SouthernSilveradoGuy85]

Your not going to be able to convince southernsilveradoguy. He has his mind made up and will argue his opinion to the death. I promise.

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 level

 

 

He knows. But, that's what happens when someone is both opinionated and hard headed. But, it's seems hard to change anyone's mind on here so I guess most people on here are also hard headed.

[Knotsure]

 

 

He knows. But, that's what happens when someone is both opinionated and hard headed. But, it's seems hard to change anyone's mind on here so I guess most people on here are also hard headed.

.

 

No we are not hardheaded!!!!

 

Lol, point proven[emoji51]

 

 

2014 Chevy silverado Z71 DCSB w/Bilstein 5100 level

[Silverado Steve]

Jon could of saved us all a lot of time effort and pain had he posted several days ago...lol

 

This is all i was asking for many posts back, info that backed the claim that our current platform could modulate torque like a modern awd system as truckguy stated. All the info i was able to find, including the video i posted from GM stated the system switches into 4wd upon recognition of the rear wheels, nothing about any modulation of torque to the front axle. I have noticed a slight amount of wheel hop on one occasion while engaged in 4auto while attempting to park on an ice glazed parking lot; so either my truck has a slip clutch going out in the transfer case, it was an anomaly, or it was those rare instances where the traction needed happened while my system was in the process of transferring power to the front axle or the transfer case or didn't reduce power in the amount of time the incident happened. I still wouldnt refer to my system as AWD, someone mentioned their DIC displays AWD while in 4 auto, that must be a change on newer models, mine says 4wd system shift in progress when i move my dial to 4auto.