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traction control on/off and auto4wd


gmyeah

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So when I bought my 2008 z71 sierra in didn't come with traction control. That's fine...no worries...no issues, but I've come to like the auto4wd......especially when my wife hops in the truck solo in so-so winter weather and i can just let her leave it in auto 4wd.

and honestly, i kinda like it myself too.

 

so i've test driven a few 2015 GMs basically just like mine....same features, etc.......but i notice it has traction control on all of the time. that's fine, and i get you might want to turn that off if in a stuck situation and want all power with the rear wheels, but with traction control on, what's the need for the auto4wd option. in a snow filled parking lot my 08 z71 with auto 4wd....i can hit the gas and it will get up and go. i'm assuming the same happens with just traction control on on the 2015?

 

with all manufactures of trucks essentially coming with traction control standard, if i saw a truck without the auto4wd (being that I like how mine works) is that a big deal?

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When in 4x4 the computer turns TC off. With how winter weather is in my area auto 4x4 in some situations is much better than just putting it in 4hi. I only used auto maybe twice this past winter. When the roads are completely covered I just put it in 4hi. When things are melting where it's patches and not consistent then I put it in auto. It's not unusual here for it to snow at night and get up into the 40s during the day to do a lot of melting and then get below freezing at night again to refreeze everything. Not having auto isn't a big deal, my '98 didn't, but it's a nice feature for certain winter situations. If I had to choose I would pick auto 4 but that's just because of how winter sometimes is in my area. TC and stabilitrak are great when it rains, but isn't a must since I did fine in rain with my '86 and '98 Chevys.

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Everyone has their opinion on traction control, mine is that I like it in the winter, on a RWD vehicle. I do not have 4wd, and do not run snow tires in the winter. I live in a city environment. In the last 5 years I have had zero issues of getting stuck, or getting into trouble in the snow. I am not the fastest on the road, or the best handling, but, truck is very predictable, and that is all you can really expect.

 

Big thing to remember about 4wd is that it is great for pulling away, but, 4wd does not help much stopping or turning the truck. 30 years when I was living in the snow belt it was quite common to see people in the ditch in their 4wd simply because of overconfidence.

Not quite sure where your going with this, but if you have info on the auto4wd, that would be great. I'm in just about every environment of weather. I don't want to debate how to drive (or stop) in bad weather.

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He's not talking about 4wd in general, just the auto 4x4 feature.

Good point here....just really talking about the auto 4wd system. Thanks for all the good info. I read up a few years ago on how the different systems work.....even within just the part-time 4wd systems. I've always generally had part time 4wd systems and yes they are great....I really like it, and without getting into all the technical details....it is way more capable than an auto4wd or awd system (and yes, those are very diff too). My point on asking about the a4wd is that's its kinda nice to have that as an option when the roads are so-so. With one of my current vehicles (the 08 sierra without traction control) It's nice when pulling out of a driveway with some snow on the end of it on a day where the roads partly covered to have it in a4wd. That way if you go around a corner that is dry, you're not ripping uf your drivetrain. and say a friend/wife, whomever hops in the truck. It's a beautiful thing to say leave it in auto4wd and forget about it on that so-so day.

 

So fast forward to today with traction control. On that so-so crappy day, does the traction control system buy you much (if you weren't to have the a4wd). I ask because when I hit the gas a bit on a 2015 1500 with traction control in a snow covered parking lot, it was actually pretty hard to spin the truck around. That was without the a4wd on.

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Traction control and 4WD are very different systems. Traction control applies the brakes at the spinning tire in an attempt to move the vehicle. 4WD applies power to up to 4 tires ( depending on limited slip etc ) in an attempt to get vehicle moving. I'll take 4WD anytime if the goal is just to get through the snow/mud. Both systems are better.

 

 

Every vehicle that I have owned with traction control would alter engine tune settings to help regain traction. Usually stating off by retarding the timing, then by selective cylinder control. None ever used the brakes. Stabilitrak is likely what you are confusing with traction control, and those two are very different systems as well. Stabilitrak will apply brakes to whatever wheel it figures will straighten the car/truck out. And it does not help with fish tailing, it activates based on yaw signals, like from understeering or drifting.

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Everyone has their opinion on traction control, mine is that I like it in the winter, on a RWD vehicle. I do not have 4wd, and do not run snow tires in the winter. I live in a city environment. In the last 5 years I have had zero issues of getting stuck, or getting into trouble in the snow. I am not the fastest on the road, or the best handling, but, truck is very predictable, and that is all you can really expect.

 

Big thing to remember about 4wd is that it is great for pulling away, but, 4wd does not help much stopping or turning the truck. 30 years when I was living in the snow belt it was quite common to see people in the ditch in their 4wd simply because of overconfidence.

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Per GM " If the engine torque reduction does not eliminate drive wheel slip, the EBCM will actively apply the drive wheel brakes. During traction control braking, hydraulic pressure in each drive wheel circuit is controlled to prevent the drive wheels from slipping. The master cylinder isolation valve closes in order to isolate the master cylinder from the rest of the hydraulic system. The prime valve then opens in order to allow the pump to accumulate brake fluid in order to build hydraulic pressure for braking. The drive wheel inlet and outlet solenoid valves then open and close in order to perform the following functions:

 

I just trying to show that they are very different systems.

For pure go in the snow/mud It's 4WD all day long. Traction control will not get you there.

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Not quite sure where your going with this, but if you have info on the auto4wd, that would be great. I'm in just about every environment of weather. I don't want to debate how to drive (or stop) in bad weather.

 

My point is quite simple, having any kind of 4wd can lull you into a sense of security/confidence. Even auto 4wd does this. Drivers that are not familiar with what is actually going on in a 4wd/auto4wd vehicle can become over confident in the traction they THINK they have. Not saying auto4wd is bad, just saying that it should not be considered a complete driving aid. The auto4wd is very handy in the urban environment when compared to manual 4wd. Running manual 4wd on dry pavement is hard on driveline, having the auto4wd avoids that. Just remember there is the issue of over confidence.

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Maybe this has been beat to death but -

Auto 4WD on my 2011 GMC makes it essentially like the AWD on our Jeep SRT. Mostly RWD unless it needs to put power to the front in a slippage situation. In the Jeep you cannot turn off the Auto function. You can pull the transfer case actuator motor and make it RWD only.

Traction Control in opinion does nothing in 2WD if you have a rear locker or limited slip (except to cut power). If you don't it will apply the brakes to simulate a limited slip. This is the case with the Jeep as it has an open rear differential. If you are spinning in deep snow, etc, TC will cut power to the point you need to turn it off to get out. Or put it in Auto 4WD or 4WD.

Stabiltrac impresses me. I recently had to dodge something at high speed and I couldn't believe how the big truck handled. I can't prove it but I believe the Stabiltrac was responsible for the way the truck handled.

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Traction control and 4WD are very different systems. Traction control applies the brakes at the spinning tire in an attempt to move the vehicle. 4WD applies power to up to 4 tires ( depending on limited slip etc ) in an attempt to get vehicle moving. I'll take 4WD anytime if the goal is just to get through the snow/mud. Both systems are better.

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Traction control and 4WD are very different systems. Traction control applies the brakes at the spinning tire in an attempt to move the vehicle. 4WD applies power to up to 4 tires ( depending on limited slip etc ) in an attempt to get vehicle moving. I'll take 4WD anytime if the goal is just to get through the snow/mud. Both systems are better.

 

He's not talking about 4wd in general, just the auto 4x4 feature.

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My point is quite simple, having any kind of 4wd can lull you into a sense of security/confidence. Even auto 4wd does this. Drivers that are not familiar with what is actually going on in a 4wd/auto4wd vehicle can become over confident in the traction they THINK they have. Not saying auto4wd is bad, just saying that it should not be considered a complete driving aid. The auto4wd is very handy in the urban environment when compared to manual 4wd. Running manual 4wd on dry pavement is hard on driveline, having the auto4wd avoids that. Just remember there is the issue of over confidence.

still no clue......if you want to enter the coversation about a4wd, feel free.

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Maybe this has been beat to death but -

Auto 4WD on my 2011 GMC makes it essentially like the AWD on our Jeep SRT. Mostly RWD unless it needs to put power to the front in a slippage situation. In the Jeep you cannot turn off the Auto function. You can pull the transfer case actuator motor and make it RWD only.

Traction Control in opinion does nothing in 2WD if you have a rear locker or limited slip (except to cut power). If you don't it will apply the brakes to simulate a limited slip. This is the case with the Jeep as it has an open rear differential. If you are spinning in deep snow, etc, TC will cut power to the point you need to turn it off to get out. Or put it in Auto 4WD or 4WD.

Stabiltrac impresses me. I recently had to dodge something at high speed and I couldn't believe how the big truck handled. I can't prove it but I believe the Stabiltrac was responsible for the way the truck handled.

this helps, thanks. i guess i wasnt thinking about it with the rear locking diff. in 2wd, it does make it a bit useless the way it would cut power. thinking about my snowy parking lot example a little....it all makes sence.

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