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Auto 4WD works well in the snow and ice.


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Apart from the idiocy of wondering if engaging clutch packs and wearing driveline parts for half the year just 'cause is detrimental to longevity, I have a question.

 

 

Are the non Auto and the Auto transfer cases the same and the whole auto system boils down to a switch part number and a software update? Seems like a left field shot, but GM only charges $200 for the option. Seems pretty involved for $200 if it wasn't just a different switch and programming.

 

One wonders if buying the switch and adding the option through GM MDI TiS SPS subscription would turn a non Auto into an Auto truck.

 

It's great for transitions in town from plowed main streets to non-plowed laterals.

Edited by Epsilon Plus
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16 hours ago, Dr1ft3r said:

He still did not answer the question of whether or not Auto mode is safe to use on dry pavement which is where the heated discussion began.

 

I have watched a lot of videos and none of them specifically state that using Auto mode on dry pavement will cause a problem or premature wear.

 

This video was pretty thorough. But while this guy states that he will use 2wd most of the time he does not state if Auto mode will cause any issues at any time. However, he does warn about 4h and 4l and he specifically refers to them as the 4wd modes but does not include Auto in that category

 

https://youtu.be/mm0ZIzErAtM

 

I would argue that because in AUTO mode, there is no power flow to the front end.  Yes, the front axle is engaged but there is no power flow to cause binding and crow hop when turning.  Which that seems to be the big thing.  The only real thing I could find in GM land was this reasoning from the owners manual:

 

Driving on clean, dry pavement in 4hi or 4lo may:

 

-Cause a vibration to be felt in the steering system.

-Cause tires to wear faster.

 

 

13 hours ago, Jettech1 said:

I've read his response actually 5 times now trying to take it all in.  The one thing I didn't get from it is, is power being transferred from the transfer case to the front wheels when it 4 wheel auto?  Perhaps this might be a good analogy.  Ok, so I have a 2021 Explorer with the 2.3L turbo engine in it.  When I want to do a burnout, one foot on the brake, one on the gas...it will burn the hell out of both tires without a limited slip rear diff.  The system notices a wheel slippage from one side and will apply brakes to the other side to put power to that side as well...instantaneously.....So when in 4 auto, is the transfer case really putting power to the front differential, when not needed?  Why would it?  If my cheap ass Explorer can sense a different wheel spin and slippage, then apply power to the other wheel seamlessly, why wouldn't the 4 auto do the same thing?  And transfer the power to the front wheels....ONLY, when needed??? 

 

 

In AUTO.  You are driving down the road, sunny dry day.  The front axle is engaged as it would be.  The clutch pack in the transfer case will allow for 0-5ft.lbs of torque to be sent through if there is no demand for 4 wheel drive.  I'd have to sit and watch live data but I would think that if you tried to "do a burnout" that the transfer case control module via its monitoring of wheel speed data will see the increase quick enough that it would full apply the clutch in the case and activate power to the front axle.  Ergo, it wouldn't let you do a burnout.  This can be backed up IMO by doing say a 0-60 or 1/4 mile launch in AUTO mode.  

 

 

5 hours ago, Epsilon Plus said:

Apart from the idiocy of wondering if engaging clutch packs and wearing driveline parts for half the year just 'cause is detrimental to longevity, I have a question.

 

 

Are the non Auto and the Auto transfer cases the same and the whole auto system boils down to a switch part number and a software update? Seems like a left field shot, but GM only charges $200 for the option. Seems pretty involved for $200 if it wasn't just a different switch and programming.

 

One wonders if buying the switch and adding the option through GM MDI TiS SPS subscription would turn a non Auto into an Auto truck.

 

It's great for transitions in town from plowed main streets to non-plowed laterals.

 

 

No.  Non AutoTrak cases do not have that clutch pack.  No software update to turn one into an auto truck.  

 

Inside of the AutoTrak case:

 

auto.thumb.png.49379e0752b040a62f2f3f76dfe3b109.png

 

(1)Transfer Case Input Shaft

(2)Transfer Case Scissor Mechanism Lever

(3)Transfer Case Four Wheel Drive Clutch

(4)Transfer Case Front Output Shaft Drive Chain Assembly

(5)Transfer Case Rear Output Shaft

(6)Transfer Case Two/Four Wheel Drive Actuator Shaft Gear

(7)Transfer Case Front Output Shaft

(8)Transfer Case Two/Four Wheel Drive Actuator Cam

 

2, 3, 6 and 8 are the key bits to the AUTO mode.  

 

 

Inside the non AutoTrak transfer case:

 

nonauto.thumb.png.246c0493f5d8b6392455ee6ed8eaaa37.png

 

(1)Input Shaft

(2)Two/Four Shift Fork

(3)Drive Chain

(4)Rear Output Shaft

(5)Control Actuator Shaft

(6)Front Output Shaft

(7)Drive Actuator Cam

Edited by newdude
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1 hour ago, newdude said:

 

I would argue that because in AUTO mode, there is no power flow to the front end.  Yes, the front axle is engaged but there is no power flow to cause binding and crow hop when turning.  Which that seems to be the big thing.  The only real thing I could find in GM land was this reasoning from the owners manual:

 

Driving on clean, dry pavement in 4hi or 4lo may:

 

-Cause a vibration to be felt in the steering system.

-Cause tires to wear faster.

 

This confirms my thoughts on this topic as well. Since there is no binding in Auto there would not be adverse wear on the 4wd components outside of normal wear and tear from usage. So, while it's not fuel efficient to use Auto all of the time, it will not be detrimental to use it all of the time. I.E. use it as you please.

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4 hours ago, Dr1ft3r said:

 

This confirms my thoughts on this topic as well. Since there is no binding in Auto there would not be adverse wear on the 4wd components outside of normal wear and tear from usage. So, while it's not fuel efficient to use Auto all of the time, it will not be detrimental to use it all of the time. I.E. use it as you please.

Yeah but, but, but what about huge burnouts all over the intersection or drifting around a round about? 
 

I just watched fast and the furious, sorry!

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Yes, if you run in Auto, there's going to be more wear on the transfer case.  In Auto on dry pavement, I cannot envision a scenario where the computer would start transferrring power to the front wheels during normal driving.  

 

We live in Florida and really only use it during heavy rains while on the highway.  Makes Dad feel good that his wife and children have an added measure of safety while driving.

 

As mentioned earlier, I've read many posts on this and other forums over the years of transfer cases requiring overhaul well under 100K miles because the people left it in Auto all the time.  This makes even more sense now that I understand properly how the whole thing works!  As always, to each, his own.

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2 hours ago, Pryme said:

Yeah but, but, but what about huge burnouts all over the intersection or drifting around a round about? 
 

I just watched fast and the furious, sorry!


I don't think you can in Auto, lol.

I work with machines and I know that machines like to be used. A machine that sits for too long will die an early death. A machine being used often will stay well lubricated and will not wear down as fast as a machine that is only used every once in a while. Because the lubrication in the rarely used machine will settle and break down causing metal on metal contact when it is fired up. If the machine is used often then the lubrication gets replenished from the reservoir of lubrication which helps keep it fresh and not deteriorated. A 4wd system is just another machine. Make of that what you will.

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