Auto 4WD works well in the snow and ice.

sheath · January 1, 2023

Had a great opportunity to try out the effectiveness of Auto 4WD function. Short story is the Auto 4WD worked seamlessly in snow and ice conditions. Much better than expected. I could tell when it was engaging by how the steering felt, but my passenger couldn't tell when it was engaging/disengaging. The truck just felt very planted and stable.

Everything I had read lead me to believe the Auto 4WD would be a bit clunky in use. Even from the GM site the way they explained it seemed not ideal.

In use (Pulling a bit more than 6,000 lbs double axle trailer through two snow covered and icy steep passes) it feels very much Like the Jeep QuadraTrac II system in our previous Grand Cherokee, which is amazing on snow and ice. I was under the impression that Auto 4WD just engaged and disengaged the transfer case as needed. It seems different than that. Like the transfer case is always engaged, but there is some kind of very smooth and immediate torque splitting.

In concert with the Tow/Haul mode engaging Auto 4WD limited the upshifts to higher rpm even under light throttle input. My WAG is it has throttle and transmission programming to smooth torque application.

Would be interesting to read other's input from those of you who have used the Auto 4WD function in slippery conditions.

It would also be great to find out how it really works (like a white paper that explains all the facets of what selecting "Auto" effects), rather than just the marketing info.

Happy New Year! Hope everyone is safe, healthy, and happy in '23. :cheers:

Pryme · January 1, 2023

1 hour ago, sheath said:

Had a great opportunity to try out the effectiveness of Auto 4WD function. Short story is the Auto 4WD worked seamlessly in snow and ice conditions. Much better than expected. I could tell when it was engaging by how the steering felt, but my passenger couldn't tell when it was engaging/disengaging. The truck just felt very planted and stable.

Everything I had read lead me to believe the Auto 4WD would be a bit clunky in use. Even from the GM site the way they explained it seemed not ideal.

In use (Pulling a bit more than 6,000 lbs double axle trailer through two snow covered and icy steep passes) it feels very much Like the Jeep QuadraTrac II system in our previous Grand Cherokee, which is amazing on snow and ice. I was under the impression that Auto 4WD just engaged and disengaged the transfer case as needed. It seems different than that. Like the transfer case is always engaged, but there is some kind of very smooth and immediate torque splitting.

In concert with the Tow/Haul mode engaging Auto 4WD limited the upshifts to higher rpm even under light throttle input. My WAG is it has throttle and transmission programming to smooth torque application.

Would be interesting to read other's input from those of you who have used the Auto 4WD function in slippery conditions.

It would also be great to find out how it really works (like a white paper that explains all the facets of what selecting "Auto" effects), rather than just the marketing info.

Happy New Year! Hope everyone is safe, healthy, and happy in '23.

Nice to hear it works nicely. I have the auto 4wd ver 1.0 which works like this…

you pull out of the garage and if you see snow on the road your finger automatically hits the 4hi button.

I crack myself up.

Have a good new year everyone!

Jettech1 · January 1, 2023

16 hours ago, Pryme said:

Nice to hear it works nicely. I have the auto 4wd ver 1.0 which works like this…

you pull out of the garage and if you see snow on the road your finger automatically hits the 4hi button.

I crack myself up.

Have a good new year everyone!

Me too buddy..... press 4hi...all is good...lol...you crack me up too...

sheath · January 1, 2023

16 hours ago, Pryme said:

Nice to hear it works nicely. I have the auto 4wd ver 1.0 which works like this…

you pull out of the garage and if you see snow on the road your finger automatically hits the 4hi button.

I crack myself up.

Have a good new year everyone!

lmao.

Definitely a legend in your own mind.

MTU Alum · January 2, 2023

It's a pretty nice system. It doesn't wait for rear wheels to slip for it to engage the front. The transfer of torque is based on driver and vehicle behavior to prevent clunky engagement. It tries to predict when slip would occur and transfer torque before it occurs.

#iworkforGM

Jettech1 · January 2, 2023

38 minutes ago, MTU Alum said:

It's a pretty nice system. It doesn't wait for rear wheels to slip for it to engage the front. The transfer of torque is based on driver and vehicle behavior to prevent clunky engagement. It tries to predict when slip would occur and transfer torque before it occurs.

#iworkforGM

And how lucky are we to be living in this time period? I remember having to get out of my truck and locking in the front hubs...and that stupid stick on the floor to put it all in 4wd......trust me, we are living in the best world.....I promise you that!!

swathdiver · January 2, 2023

On 12/31/2022 at 8:46 PM, sheath said:

... it feels very much Like the Jeep QuadraTrac II system in our previous Grand Cherokee

It ought to as they both use the Magna MP3023 transfer case! GM started using it in 2009 and Jeep shortly thereafter if memory serves.

sheath · January 2, 2023

2 hours ago, swathdiver said:

It ought to as they both use the Magna MP3023 transfer case! GM started using it in 2009 and Jeep shortly thereafter if memory serves.

Thanks James. I found this article based on your post.

https://www.transmissiondigest.com/the-magna-powertrain-mp3023-3024-nqh/

When I read the marketing info, I was just like Pryme & Jettech1. It sounded to me like all it did was engage/disengage the 4WD Mode. I may be getting old, but I can still turn button as needed.

Pryme had me cracking up with his post, because that is exactly what I was thinking when I ordered the truck. It was my GF who talked me into upgrading to the Auto function. Now I'm glad she did.

Davew277 · January 2, 2023

Auto is nice. My Jeep uses it all of the time. There is no 2wd option in my Jeep. The difference between our trucks and my Jeep is that in my Jeep there is no 4wd high option. There is a 4wd low option and 5 different auto options to choose from (auto, snow, mud, etc...). It's always on auto unless I'm not on clean pavement. I leave it on auto for rain, but when it snows I usually select the snow option, but I have forgotten to select it a few times.

I use 4wd low when I'm on my property in the Ozarks since I'm not even on gravel there. It's just dirt, rocks, foliage and tree stumps. I had to carve my own trails through the trees with a chainsaw for my Jeep and my ATV.

I plan to use auto all of the time on my 3500 too. I don't see any good reason to not use it. It only engages when it's needed. Otherwise it's in 2wd.

shadow gray 2020 hd · January 2, 2023

17 hours ago, Jettech1 said:

And how lucky are we to be living in this time period? I remember having to get out of my truck and locking in the front hubs...and that stupid stick on the floor to put it all in 4wd......trust me, we are living in the best world.....I promise you that!!

My 98 k2500 has a "stupid stick" floor shifter.

Don't have the auto 4wd in my 2020 2500, like others mentions just hit 4 hi. My dodge Durango is all time awd, it just goes and rarely ever slips.

Jettech1 · January 2, 2023

3 hours ago, shadow gray 2020 hd said:

My 98 k2500 has a "stupid stick" floor shifter.

Don't have the auto 4wd in my 2020 2500, like others mentions just hit 4 hi. My dodge Durango is all time awd, it just goes and rarely ever slips.

But great memories though of that stupid stick on the floor. Freezing my butt off to lock the front hubs in....great memories...

swathdiver · January 2, 2023

6 hours ago, Davew277 said:

I plan to use auto all of the time on my 3500 too. I don't see any good reason to not use it. It only engages when it's needed. Otherwise it's in 2wd.

When in Auto, the front driveshaft is spinning. You will wear out the transfer case prematurely by leaving it in Auto, these are not AWD transfer cases with a planetary and made to run on any road surface all the time. Use it when you think you'll need it and then switch back to 2HI.

Jettech1 · January 3, 2023

16 minutes ago, swathdiver said:

When in Auto, the front driveshaft is spinning. You will wear out the transfer case prematurely by leaving it in Auto, these are not AWD transfer cases with a planetary and made to run on any road surface all the time. Use it when you think you'll need it and then switch back to 2HI.

You make a great point here, but, and I'm curious here. When it Auto, that I don't have, shouldn't the front diff only be powered when it senses slippage?

Pryme · January 3, 2023

Even in 2023 I know of at least the 4Runner trd off road still uses the mechanical lever to engage 4wd. There is something to be said for the mechanical lever vs having to rely solely on electronics though.

swathdiver · January 3, 2023

2 hours ago, Jettech1 said:

You make a great point here, but, and I'm curious here. When it Auto, that I don't have, shouldn't the front diff only be powered when it senses slippage?

Yes, but the transfer case is engaged and spinning the front prop shaft. When the computer decides more traction is needed, it engages the front differential.

If you google around you can find a write up on how AUTO works.