StabiliTrak on Suburban / Yukon 4x4

The systems in general, use a variety of sensors that can tell when a vehicle is headed for a potential spin or spill.

The systems will apply the brakes automatically to individual wheels while reducing engine power to forestall disaster

Most important, regardless of # of tires being driven, is the condition of the tires. Good tires on a 2 wheel drive will work better than 4 hard or bald tires on a 4 wheel drive.

StabiliTrak does not contain or add 4WD or AWD (all-wheel drive - I think full-time AWD is an option only on the Escalade and Denali). StabiliTrak just brakes individual wheels and/or adjusts engine torque to help keep you going in the direction you want to go - it does not add power to the front wheels if in a 2WD vehicle.

Now can you add the StabiliTrak > We are in the process of purchasing a Suburban. We are using this

Are you sure that you can get AWD with Stabilitrak on a plain Suburban? I've only seen the systems on higher end trucks like the Denali, Cadillac Escalade, and the Avalanches. Perhaps you can get it now on the Suburbans.

Anyway, the AWD versions with Stabilitrak has a transfer case and front diff that is always engaged. There are no mechanical components to limit torque (like posi-trac, or viscous couplings) the system relies on the ABS system to stop wheels from spinning as it occurs. The Stabilitrak system also uses the ABS system to apply the brakes at each corner as necessary to keep you from going into a spin. I've only had a chance to road test the feature on a Cadillac car (STS), but it really is quite amazing. Especially in low traction conditions....I threw the steering wheel all over the place and you couldn't get the car to go into a spin.

The other system, the Auto4Wheel drive, probably responds quicker and better when you need 4 wheel drive. It uses a clutch pack in the transfer case that applies torque to the front wheels as needed in low traction condition. You also have the option of just sticking it into 4 wheel drive on a permanant basis, which should only be used in really low traction conditions. The only con to this system is that it will require more maintenance and repairs then the AWD system. We see lots of mechanical failures with this system. You can avoid this by, changing the diff and t/case fluids on a regular basis (every 30K miles) and leaving the vehicle in 2Hi at all times and only using the Auto4Hi feature when you absolutely need it.

Ian

Thanks for the thoughts - so as far as 4 driven wheels - that would be no? I amy buying a new car - bald tires are not an issue. I understand waht Stabilitrack does and why it is good, but not how it effects

4wd/awd. If Stabilitrak diables 4wd i'm not sure it is a plus over "automatic" 4wd. Also, why pay for 4wd if it is going to be off? The sales stuff does not make the interaction begtween these options clear. -JAX

A good summation, as usual. John, it appears that Autotrak and Stablitrak have been confused. The Autotrak would be very worthwhile purchase, but run it as noted, in 2HI except when roads are slippery, then use the Auto mode. Ask the dealer or one of the web sites about the availability of Stabi with Autotrak. Depends on the trim level (options) of the vehicle. It is available on some configurations of the

4WD. Remember that 4WD will not help you st>John wrote:

As far as I know, you cannot have Stabilitrak with a regular 4x4 system. Stabilitrak needs to be able to independently regulate wheel speed at each corner, and mechanical devices that regulate torque would simply interfere with it's operation. If you get a vehicle with AWD, nothing can "disable" it. It's in permanent

4x4 mode, but with no mechanical means to control torque output at the wheels. This is where Stabilitrak comes in, it uses the ABS system to control wheel spin. You can actually get the AWD system on full size vans, but what they do in this case (because Stabilitrak is not available on the full size vans) is simply insert a silicone based viscous coupling in the same t/case that is used with the Stabilitrak system. And you can also get the regular old locking diff in the rear.

I realize snow is not on the ground yet, but in my view, the very best thing would be to be able to road test both systems and attempt manuevers that will test both systems. My only complaint about the Stabilitrak/AWD systems is that it seems to be slower to control wheel spin and you can actually get the truck sideways before the system "catches" it.

By the way, I still think that for a combination of low maintenance and good useability, the manual style of

4x4 is the best. I know that you can get this on regular trucks, I'm not sure you can order that option on the Suburban. You might not like the idea of having to pull a lever on the floor, but believe me, very low maintenance. You get the versions with all the fancy buttons and electronics....big money when the components go south.

Ian

As far as what is available, here is an abreviated listing from the Chevy web site of a similar vehicle;

2004 Suburban 1/2-Ton 4x4

On page:

Note 4 says: "Open differential transfer case replaces Autotrac when available StabiliTrak is selected." ... so that does seem to suggest something more than just 2WD (but probably not 4WD or AWD)

Welll I really meant that it probably is *not* AWD but rather a lesser variation of the 4wd AutoTrac ... I wonder what the open transfer case diff means re: power to the front wheels ...

Yep, that's the AWD version. I forgot that you can select 4 low, all that happens is that the front and rear axles are locked together thru the transfer case. I discovered this one time on an Escalade...had to remove the front diff and front driveshaft. Normally, on an Autotrac version, you can just drive it out on the rear driveshaft....on this one, you have to shift into 4 low to be able to move without the front diff in there.

I must not be explaining things very well. It's AWD.....it will work.... just differently then your normal 4x4 system. You will not get stuck with it.....you will be able to run around in the snow just all the trucks with regular style 4x4.

Ian

What it means is that if there were no Stabilitrak on a vehicle with an open transfer case diff.....you would only have power flowing to all the wheels as long as each wheel was on a high traction surface. As soon as wheel began to spin, it would simply spin, as there is no mechanical mechanism like a clutch pack, viscous coupling, or antilock diff, to limit wheel spin. This would be a useless system. But if you add Stabilitrak that uses the ABS system to apply the brakes individually to each wheel when necessary, then you don't need mechanical devices to perform the torque limiting part of this whole equation.

Let's say that you start to spin the left front wheel, Stabilitrak applies the brake at the left front wheel.....because of the open diff at the front, power will flow to the right front wheel... then it begins to spin.....Stabilitrak applies the right front brake system.....now power has to flow thru the t/case (open diff in it) back to the rear wheels. Of course, all this happens quite quickly...but not as quickly as the mechanical systems.

This is mainly intended for yuppies, pimps, rap artists...etc who want to drive a big fancy truck and don't want to pull levers or push buttons....just want to drive....and have the vehicle make sure they don't end up in the ditch.

Ian

Well, I'm still trying to figure out if we are yuppies, pimps, rap artists... or.. etc. I think I'm an etc. :)

From the descriptions here (A lot more than anything on the Chevy site) I think that 4WD+Stabilitrack is a valid technology to improve safety (have the vehicle make sure my kids don't end up in the ditch and "you will be able to run around in the snow") - I will be picking up the vehicle tomorrow.

After I get it and find something slippery to skid about on I will let you know how it really works.

Thanks for your input.

-JAX

Sorry, that probably wasn't the best way to describe who is looking for these types of systems. There isn't anything wrong with people wanting what I would refer to as a "set it and forget it" type of system. Many more people these days seem to want their driving experience to be something where the vehicle just does what they want without the need for all sorts of personal intervention.

Ian

StabiliTrak is not 4WD, it is AWD, meaning that all four wheels are engaged at all times. It is impossible to put it in 2WD Hi, and you get about 3MPG less than a 4WD in 2WD Hi. Tire wear is also increased on the front tires.

The window sticker on my Suburban states that it is 4WD, and nowhere suggests that it is actually AWD. The Chevrolet dealer in Columbia IL who sold me the vehicle also did not know that it was AWD until I brought it to their attention. Although this is the thirteenth Suburban I have owned, neither the dealer nor Chevrolet will do anything to address this.

Anyone buying a GM vehicle with Stabilitrak should make sure that he understands what he is getting.

I read all of your correspondence here, and am wondering if your conclusion was that in a suburban, if you get a 4wd version (non z71) with stabilitrac, what you are really getting is the same as the Denali AWD system? It makes sense, I don't think GM has engineered 2 different systems but they want to be vague as to keep the Denali up on a pedestal as something just a bit better. It's a bit frustrating that they don't (at least i haven't found it yet) put out anything that explains the system a bit more technically so you know what you're getting! How are you liking it? Your question was basically the same thing as mine, so basically i was wondering what your conclusion was after having the vehicle? I drive a ML 320 mercedes and i love the esp (their version of stabilitrac) it's in an awd version, i "played" on some snow and ice and could not lose control if i wanted to. I need a bigger car, don't really like the denali's "customized" look and want to know i'm getting the same thing in a suburban.. any help would be appreciate. Thanks

As far as I know, any GM truck that uses Stabilitrak with a 4 wheel drive system will automatically be using an AWD system with an open transfer case. Since the Stabilitrak system does all of the torque management by applying the brakes independently at each wheel, there is no need for any torque management inside the t/case. There are two different styles that I've seen, one is a one speed system, completely open t/case....the other has a provision for low range, but in high range the t/case is open, in low range the t/case is basically mechanically locked front to rear. So in low range, torque management is handled by the t/case (makes sense at those low speeds) and in high range, it reverts back to Stabilitrak to manage the torque.

Ian