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AWD Question Sierra 1500 Z71 2017

4x4awd sierra 2017

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#16 Silverado Steve

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Posted 11 January 2017 - 11:58 AM

A center differential only manages torque to the front and the back

 

A smart front diff? I think you mean a smart center diff. Our front diffs are just regular open diffs

I think it would help if you googled difference between All Wheel Drive and 4WD. Our front diff has a clutch that senses wheel slip and the transfer case will apply up to 50% power. Modern All Wheel Drive systems apply power to all 4 wheels a 4WD system does not. An All Wheel Drive system also allows each wheel to turn at different speeds. In the case of Subaru, their system can cut power to one wheel and transfer power to another, our system does not. In reality, all our system does is takes the judging of when to turn the knob to 4HI



#17 truckguy82

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Posted 11 January 2017 - 11:59 AM

I think it would help if you googled difference between All Wheel Drive and 4WD. Our front diff has a clutch that senses wheel slip and the transfer case will apply up to 50% power. Modern All Wheel Drive systems apply power to all 4 wheels a 4WD system does not.An All Wheel Drive system also also allows each wheel to turn at different speeds. In the case of Subaru, their system can cut power to one wheel and transfer power to another, our system does not. In reality, all our system does is takes the judging of when to turn the knob to 4HI

No no no, that is completely wrong and it's what I used to think

 

I guess you are not reading what I write.

 

When you are in 4wd auto, there is nothing locked even when it is engaged


Edited by truckguy82, 11 January 2017 - 12:03 PM.


#18 Silverado Steve

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Posted 11 January 2017 - 12:03 PM

I'm not going to debate the semantics with you. I have a full understanding of how our system works, it's spelled out in our OM's. Our truck does not have a torque managing differential that manages power to all 4 wheel independently, it only manages power to the front axle, a totally different concept and that what differentiated 4 Auto from All Wheel Drive. I think you are missing the big point which is power is constantly applied to All Wheels in All Wheel Drive, that is not the case in 4 Auto.



#19 kstruckcountry

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Posted 11 January 2017 - 12:07 PM

We've been over this a few times. Last time we hashed out that Subaru currently uses 3 different systems, so comparing the pickups to them gets confusing, especially since it's an entirely different system.

2hi: transfer case and front axle disengaged.

4auto: front axle engaged, transfer case engaged at a very small torque, and ramped up as needed, up to a full lock.

4hi: front axle engaged, transfer case locked to send same power to both ends, all the time.

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#20 truckguy82

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Posted 11 January 2017 - 12:08 PM

I'm not going to debate the semantics with you. I have a full understanding of how our system works, it's spelled out in our OM's. Our truck does not have a torque managing differential that manages power to all 4 wheel independently, it only manages power to the front axle, a totally different concept and that what differentiated 4 Auto from All Wheel Drive. I think you are missing the big point which is power is constantly applied to All Wheels in All Wheel Drive, that is not the case in 4 Auto.

Ok don't debate, because you are incorrect. There is no single differential that manages power to all 4 wheels lol. There is a system to manage the front and rear bias, sometimes known as the center diff, and systems to manage the rear left/right, and the front/left right, these are usually known as the front and rear diff.

 

Do you know how a modern awd vehicle (not a high end awd system) manages torque to individual wheels? If one wheel is slipping the car applies the brakes to that wheel! There is no complex system routing power to the wheel that has traction, it's just a brake caliper engaging to force the open diff to apply power to the other wheel.



#21 Silver 5.3

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Posted 11 January 2017 - 12:12 PM

From the 2014 Owners manual..."AUTO (Automatic Four-Wheel Drive): This setting is ideal for use when road surface traction conditions are variable. When driving the vehicle in AUTO, the front axle is engaged, and the vehicle's power is sent to the front and rear wheels automatically based on driving conditions. Driving in this mode results in slightly lower fuel economy than Two-Wheel Drive High. Do not use AUTO mode to park on a steep grade with poor traction such as ice, snow, mud or gravel. In AUTO mode only the rear wheels will hold the vehicle from sliding when parked. If parking on a steep grade, use 4 m to keep all four wheels engaged." 

 

From GMC's website..."If road conditions frequently alternate between high- and low-traction areas, consider using the “AUTO” setting found on select GMC electronic transfer cases. This setting allows your GMC to automatically distribute torque to the front axle by anticipating the need for additional traction. Shifting into “auto” engages the front axle, but the transfer case sends power primarily to the rear wheels in normal conditions and the clutches modulate torque forward to provide stability and enhance traction to the vehicle. Although not always optimal for efficiency and wear of your vehicle 4wd driveline, AUTOMATIC 4 HI can be used on any road condition without risk of damaging your vehicle."

 

So based on this, it is not "true" AWD.


Edited by Silver 5.3, 11 January 2017 - 12:13 PM.


#22 Silver 5.3

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Posted 11 January 2017 - 12:17 PM

And when you compare it to the Acadia AWD system, it sounds different "Acadia All Terrain’s ability lies with its advanced twin clutch all-wheel drive system. Not only can this system send power to the rear wheels as needed, but it can detect if either one of the rear wheels is slipping, and actively send power to the wheel with the most traction, essentially functioning like a limited-slip differential."



#23 truckguy82

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Posted 11 January 2017 - 12:19 PM

From the 2014 Owners manual..."AUTO (Automatic Four-Wheel Drive): This setting is ideal for use when road surface traction conditions are variable. When driving the vehicle in AUTO, the front axle is engaged, and the vehicle's power is sent to the front and rear wheels automatically based on driving conditions. Driving in this mode results in slightly lower fuel economy than Two-Wheel Drive High. Do not use AUTO mode to park on a steep grade with poor traction such as ice, snow, mud or gravel. In AUTO mode only the rear wheels will hold the vehicle from sliding when parked. If parking on a steep grade, use 4 m to keep all four wheels engaged." 

 

From GMC's website..."If road conditions frequently alternate between high- and low-traction areas, consider using the “AUTO” setting found on select GMC electronic transfer cases. This setting allows your GMC to automatically distribute torque to the front axle by anticipating the need for additional traction. Shifting into “auto” engages the front axle, but the transfer case sends power primarily to the rear wheels in normal conditions and the clutches modulate torque forward to provide stability and enhance traction to the vehicle. Although not always optimal for efficiency and wear of your vehicle 4wd driveline, AUTOMATIC 4 HI can be used on any road condition without risk of damaging your vehicle."

 

So based on this, it is not "true" AWD.

 

I repeat, in auto4, when our trucks detect slip and engage 4wd, it does not simply engage 4hi.

 

What everybody thinks it does and what I used to think

 

4auto mode - 100% rwd, when rear slips, it's locked 50/50 to power the front, just like a fast activating 4hi button

 

what it really does

 

4auto mode - 90-100% rwd, when rear slips, it can continuously alter torque split to front and rear



#24 truckguy82

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Posted 11 January 2017 - 12:21 PM

And when you compare it to the Acadia AWD system, it sounds different "Acadia All Terrain’s ability lies with its advanced twin clutch all-wheel drive system. Not only can this system send power to the rear wheels as needed, but it can detect if either one of the rear wheels is slipping, and actively send power to the wheel with the most traction, essentially functioning like a limited-slip differential."

yeah so it does the same exact thing as our trucks, except we have a mechanical locking rear end, and the acadia has a limited slip rear end.

 

Also ours in rwd bias and the acadia is FWD bias


Edited by truckguy82, 11 January 2017 - 12:23 PM.


#25 Bushleaguechew

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Posted 11 January 2017 - 12:35 PM

You guys do realize there are many different types of AWD systems right? Some are mechanical, some are electronically controlled, some send power to the rear only when needed and some send power to all 4 wheels at all times.

http://www.caranddri...-system-feature


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#26 Silverado Steve

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Posted 11 January 2017 - 12:45 PM

Bushleaguechew posted a very good article that points out the difference between the two systems. As I have mentioned several time before, an All Wheel Drive system allows all 4 wheels to receive or remove power at different levels independently; hence why there is no wheel hop when there is power to the wheels and the wheels turned. Our system only allows power to the rear at the same power to both wheels, or power to the front to both, but not independently to either wheel, I don't understand what you don't get and why you continue to debate and tell everybody they are wrong?

 

yeah so it does the same exact thing as our trucks, except we have a mechanical locking rear end, and the acadia has a limited slip rear end.

 

Also ours in rwd bias and the acadia is FWD bias



#27 RhinoGuy

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Posted 11 January 2017 - 12:56 PM

Something is always engaged in the auto setting because I can feel and hear it in my truck.

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#28 truckguy82

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Posted 11 January 2017 - 12:57 PM

Bushleaguechew posted a very good article that points out the difference between the two systems. As I have mentioned several time before, an All Wheel Drive system allows all 4 wheels to receive or remove power at different levels independently; hence why there is no wheel hop when there is power to the wheels and the wheels turned. Our system only allows power to the rear at the same power to both wheels, or power to the front to both, but not independently to either wheel, I don't understand what you don't get and why you continue to debate and tell everybody they are wrong?

 

:M16:

 

There is no wheel hop in 4wdauto!!! why do you think that is??

 

You have zero understanding of how these systems work. Maybe you should read the article he posted, and then read up on ours.

 

You also have not read everything I've posted and then grasped what I was saying.

 

You are just trying your best to find evidence to support your incorrect theory, you haven't found anything. I fully understand how AWD systems operate and how 4wd systems operate, you do not.


Edited by truckguy82, 11 January 2017 - 12:59 PM.


#29 Silver 5.3

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Posted 11 January 2017 - 01:01 PM

So much anger over something that won't matter at the end of the day. 

 

"If it is something that won't matter in 5 years, don't give it more than 5 minutes of your time"--Wise Words of Wisdom



#30 truckguy82

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Posted 11 January 2017 - 01:12 PM

So much anger over something that won't matter at the end of the day. 

 

"If it is something that won't matter in 5 years, don't give it more than 5 minutes of your time"--Wise Words of Wisdom

well "wise words of wisdom" should go bang a girl with gonorrhea because that won't matter in 5 years





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