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Is it bad to run your truck in “Auto 4wd”?

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Shall36 Enthusiast

Shall36

Posted
Posted

Guys, not complex. Auto AWD in the GM trucks is designed to be used in any condition.  On dry roads, it’s only going to put power to the front wheels if you break the rear tires loose. There are other AWD systems that are full time AWD. The 4wd setting puts power up front 100% of the time. You will get binding if the wheel is turned and the tires have enough grip to not break loose. This is why any 4wd system should only be engaged when on loose roads. “Auto” is not the same as “4WD”. Auto is akin to AWD, which is different from 4WD. 
 

i personally set to 2WD unless it’s raining then I use Auto. I could leave in Auto all the time but it’s sometimes more fun to be in 2WD. 

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OnTheReel
OnTheReel

4 AUTO engages the front axles but sends very little power to the front wheels until slip is detected. The power distribution is handled by an electronic clutch in the transfer case.   In au

z1boss
z1boss

I've always ran my trucks in 4wd auto.  No issues at all.  I've noticed that the gas mileage isnt really affected either based on my testing.

Wiggums
Wiggums

Manual states slight drop in gas mileage if set on auto instead of rear wheel drive.    

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diyer2 Senior Enthusiast

diyer2

Posted
Posted

2WD to save wear, 4WD snow, mud, slippery boat ramp. 

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customboss Senior Enthusiast

customboss

Posted
Posted (edited)

Auto mode as others have said isn't 4WD until it AUTO LOCKS the transfer case.  It's the GM version of AWD on demand formerly known as Auto Trak II.  It's too slow up here most of time on gravel sand roads going up steep angles in ice and snow but good  insurance for the Missus when she's nervous. 

Edited by customboss
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  • 2 weeks later...
Davew277 Enthusiast

Davew277

Posted
Posted
On 12/7/2022 at 4:42 PM, Snakes709 said:

The more a part gets used, the more it wears down. 4auto uses clutches to activate 4wd when it detects slip. 4wd is meant to be used on low traction situations. Have you ever tried to turn sharply with 4hi or 4low on dry surfaces? It can damage the drivetrain. The clutches help minimize that so it can be used when its dry. But my question is, why would you? If the driving conditions are ideal, why would you need anything other then 2wd?  


Well, then if you use 4auto all of the time then all the drivetrain components should wear equally instead of the rear end components wearing out first, right?

What about vehicles that don't even have a 2wd option? Those aren't breaking down all of the time. I have a Jeep Grand Cherokee with full time 4wd. It's using the same technology as 4auto.

Snakes709 Enthusiast

Snakes709

Posted
Posted
20 hours ago, Davew277 said:


Well, then if you use 4auto all of the time then all the drivetrain components should wear equally instead of the rear end components wearing out first, right?

What about vehicles that don't even have a 2wd option? Those aren't breaking down all of the time. I have a Jeep Grand Cherokee with full time 4wd. It's using the same technology as 4auto.


so your theory is its better to wear out more components evenly and faster instead of wearing the rear out first and the front out later.  Ok, have fun with that. 

Davew277 Enthusiast

Davew277

Posted
Posted
14 minutes ago, Snakes709 said:


so your theory is its better to wear out more components evenly and faster instead of wearing the rear out first and the front out later.  Ok, have fun with that. 


What does it matter? Most people don't keep their vehicles long enough for either to wear out.

I have found over the years that components which are used often work for a long time. Components that are never used will not work when you finally decide to use them.

KARNUT Senior Enthusiast

KARNUT

Posted
Posted
44 minutes ago, Davew277 said:


What does it matter? Most people don't keep their vehicles long enough for either to wear out.

I have found over the years that components which are used often work for a long time. Components that are never used will not work when you finally decide to use them.

That happened to me with automatic locking hubs on my 97 Ford diesel. I should’ve engaged them once in awhile on wet roads. I found out one day when I got stuck. I ended up putting on manual locking hubs. 

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Davew277 Enthusiast

Davew277

Posted
Posted
1 hour ago, KARNUT said:

That happened to me with automatic locking hubs on my 97 Ford diesel. I should’ve engaged them once in awhile on wet roads. I found out one day when I got stuck. I ended up putting on manual locking hubs. 

 

That's why I'll be running in 4auto most of the time, unless I'm on a long trip and I'm trying to save that extra 1 mpg or so by using 2wd. Otherwise there's really no reason to use 2wd IMO. But to each their own.

Then of course I'll use 4H or 4L when it's really needed.
 

 

I think Ford is the only company that still has manual locking hubs today. Even Jeep has went completely automatic now.

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Z45 Senior Enthusiast

Z45

Posted
Posted (edited)

To add context,  I was in the GM dealer for service on Tuesday and was in the waiting room when the service manager came in to tell a customer his truck was ready to go, oil change I take it.  The customer started asking him about using 4wd, should I 4H or AUTO,  we were having some bad weather.  The SM related that the state police/co's are told to keep their 4wd Tahoe's/Silverado's in AUTO all the time (24/7) no matter what.  They have never replaced any transfer cases in any those vehicles and as you can imagine, they are driven hard. This is in Michigan where more the 50% of the time you are driving on snow and ice covered roads as well as the co's in the boonies all the time.

 

PS-The new Silverado's the CO's have are Custom Trail Boss's less any decals etc.  They even promote that every new CO's is assigned a brand new Silverado CC pu as well as boat, snowmobile, atv.

Edited by elcamino
  • 1 month later...
cabledude Enthusiast

cabledude

Posted
Posted

For what it is worth, when I bought my 2018 Sierra, the owner told me he had the transfer case replaced under warranty, the dealer told him it was likely because he left it in Auto all the time, but seldom drove on anything but dry pavement.  If I suspect there is any reason I am going to need it, I put it in Auto, if not I leave it on 2WD.  Don't know if it saves gas or not, but every little bit helps.

  • Like 1
  • 3 weeks later...
Luc1f3r Enthusiast

Luc1f3r

Posted
Posted
On 1/30/2023 at 7:49 AM, asilverblazer said:

3 pages when the proper response was in post 7.

Lets make it 4 cause i disagree :)

With 6.2 and the ultra intrusive traction control I always run in 4 auto except when on long highway trips. Saves the tires and makes the truck much more predictable when accelerating. 

Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted
4 minutes ago, Luc1f3r said:

Lets make it 4 cause i disagree :)

With 6.2 and the ultra intrusive traction control I always run in 4 auto except when on long highway trips. Saves the tires and makes the truck much more predictable when accelerating. 

How does it make it more predictable when accelerating? It only engages when it detects rear wheel slip. 

KARNUT Senior Enthusiast

KARNUT

Posted
Posted

I had a couple of auto 4wd trucks. I always had loud exhaust sometimes megaphones. Sometimes stupid mustang drivers, okay other people too would take the bait when I left the light hard in the rain. It would really piss them off. They couldn’t figure it out. It was still more fun smoking people with my modified diesels. No I didn’t roll coal, I hated that.

asilverblazer Senior Enthusiast

asilverblazer

Posted
Posted
51 minutes ago, Luc1f3r said:

Lets make it 4 cause i disagree :)

With 6.2 and the ultra intrusive traction control I always run in 4 auto except when on long highway trips. Saves the tires and makes the truck much more predictable when accelerating. 

Operating the vehicle contrary to what is described in the owners manual is not covered by warranty. :) Lead foot much in the 6.2? 

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