Driving in 4wd

[Joe_K]

Just have to say, I've owned a LOT of 4wd trucks over the years. Finally got to test it out this week in ice/snow. This is the best performing vehicle in these conditions I've ever owned. I have the 18's with SRA's.

[JCthebigTree]

you'll be supprised how much the traction improves with a few sand bags in the bed. I'm up in MN and ND and hardly ever use AUTO or 4WD on my 04' with BFG AT T/A tires, I don't have as much hope for the Goodyears on my new truck. I'm not so conserend with dammaging my drivetrain as I just don't feel it necessary unless there is a few inches of snow on the road

I had 285 BFG AT's on my old Avalanche, with the torsion keys turned up, that thing would go through ANYTHING. I'm not sure they make any that fit my 20" wheels though.

 

I threw 4 tubes in last night, definitely the expected improvement.

 

Pretty sure if you got 30" of wet snow you ain't movin'.

NBSGMC - Well, I should say it was over the course of two days, but there were times were I was probably moving through upwards of 20" without too much difficulty...only time I buried was in my driveway which is about a 20 degree slope and the way the pavement is laid out the front end dips way down before heading up the incline...would have needed a big lift to get in there.

[SEchevyz71]

I'm also in North TX. My commute is about 17 miles on US 287 to Dowtown Ft Worth and it didn't get much love from TXDOT. I left it in Auto the whole way, but locked in 4HI going across the slippery and bumpy cobblestone ice on every bridge. I saw several 2wd pickups slipping their rears almost into adjacent lanes and some small cars get stuck. Probably didn't need to be in 4HI but I didn't want to wait for the slip before it engaged fully. The last thing you want is to stop on that stuff. I had no issues.

 

 

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[Roscopcoletrain]

I used mine for the first time today here in Michigan with 4 inches of snow and it works great! Interesting thing I noticed is that it runs in V4 mode much quicker and stays in it longer....This truck is too smart for me!

 

probably in v4 more because of the light use of the gas peddle due to road conditions

[waumo1]

The auto 4WD is great in our typical winter road conditions. As near as I can tell from reading it works in the same manner as our Jeep SRT8 AWD system and modulates power to the front wheels as needed up to about 40-50%. In the Jeep it is also great for embarrassing muscle cars at take off.

[JCthebigTree]

I've figured out how to cut out the stabilitrack!

 

All you have to do is have the 4 wheel drive control module go bad and have the dealer take it out while they order a new one.

 

Sure, you don't have 4 wheel drive...but no stabilitrack either!

 

[scz71864]

btw you get worse gas milage in auto 4wd. so if you dont need it i would leave it in 2wd

[HydrogenCyanide]

btw you get worse gas milage in auto 4wd. so if you dont need it i would leave it in 2wd

Why would this be? If it is not engaging why would it be worse?

[ms55330]

Why would this be? If it is not engaging why would it be worse?

I have noticed that these and previous generations sound like they are

working harder and the acceleration isn't as fast (on clean roads) when

in AUTO vs 2WD. I'm not sure if the transfer case or front differential

are engaged but at least one is causing drive line drag while in AUTO.

hence the lower mileage but still better then the 4WD setting

[TX14Z71]

I believe Auto partially engages and that's why it may affect gas mileage.

[kstruckcountry]

Yes auto engages the front axle, but the transfer case doesn't engage until it's needed. I haven't ever really noticed it "dragging" or taking more power to move in Auto.

[MikeNH]

Auto preloads the clutch in the transfer case so the power transfer can be near instant when it is needed. This adds some drag to the driveline and thus uses more fuel.

 

 

On a side note, it seems that when in auto, power to the front wheels is not present or minimal when coasting as while turning through a few intersections the past day or so with the snow we've gotten if I use auto instead of 4 high the front end will plow ahead and skid some in those circumstances. Giving it gas gets it back in line.

[tutiii]

I leave Norht of philly, the other day we had some ice and snow. My truck says its in 2wd but ive noticed when backing up and turning i hear and feel a jerking movement. could hte truck be stuck in 4wd?

 

thanks

[MikeNH]

Doubt it. If you were in 4wd it'd feel like a binding issue when turning.

[Cap'n Pete]

Yes auto engages the front axle, but the transfer case doesn't engage until it's needed. I haven't ever really noticed it "dragging" or taking more power to move in Auto.

Exactly, front diff engages, instead of free-wheeling. I find you can feel it in the wheel, but only VERY slightly. Almost unnoticeable, unlike being in 4Hi or 4Lo, where there is no doubt you're in 4WD.

 

Auto preloads the clutch in the transfer case so the power transfer can be near instant when it is needed. This adds some drag to the driveline and thus uses more fuel. On a side note, it seems that when in auto, power to the front wheels is not present or minimal when coasting as while turning through a few intersections the past day or so with the snow we've gotten if I use auto instead of 4 high the front end will plow ahead and skid some in those circumstances. Giving it gas gets it back in line.

Exactly - with the front diff engaged, the transfer case is the last "link" between being engaged or disengaged, and there's a clutch inside doing that work. It is virtually instantaneous, and almost seamless.

 

HOWEVER, I had an issue in a previous truck (Avalanche) in AUTO, where I couldn't back up a trailer in the snow. The rear tires would spin, the fronts would begin to kick in, and as soon as the truck started to move, the fronts would stop helping again! It was creating a brutal lurching/jerking effect, and I could hear something in the drivetrain (probably the transfer case) chattering as the clutch was engaging and disengaging. It was frustrating. So I switched to 4Hi (engages the clutch 100%) and continued backing up trouble-free! So clearly, each mode has its purpose.

 

AUTO for typical driving on slick/snowy roads. 4Hi (or Lo) when you need REAL "4WD".