FWD vs AWD in snow

[Journeyman425]

_{i knew there was something else - I remembered reading it once before:}

_{The all-wheel-drive system requires no driver input or control. Under most driving conditions, it is passive and power is transmitted to the front wheels alone. The system functions to optimize traction and handling under the following conditions:}

_{Anticipates slip by responding to pedal position unlike all-wheel drive systems that rely on pumps or viscous fluids to transfer torque, the system requires no front-to-rear slippage for activation. This allows the system to transfer torque in response to accelerator pedal position. If the driver is asking for a lot of power, the system immediately starts clamping the Electronically Controlled Coupling (ECC), transferring a high percentage of power to the rear wheels. This avoids front wheel slippage, as power to propel the car is transmitted through all four tires. This mode of operation is called open-loop operation in that there is no feedback to affect the torque transfer.}

_{Modulates torque to optimize traction on slippery surfaces a second, closed loop, operating mode uses feedback from the wheel-speed sensors to determine the appropriate torque transfer. When the front wheels slip, the all-wheel-drive electronic control module tells the ECC to start clamping, sending power to the rear wheels. Attempting the same aggressive launch described above with the front wheels on ice and the rear wheels on dry pavement, the ECC sends even more torque to the rear wheels to minimize slippage and launch the vehicle. Both modes are always active and the maximum of the two is chosen. Power to the rear wheels is modulated during lost of traction while traveling at freeway speeds; for example, hydroplaning on a puddle of water, will send very little power to the rear wheels because the controller knows at those speeds a lot of power is not needed at the rear wheels.}

_{Prevents binding during low-speed turns a third condition, which is independent of the others, uses the ESP steering angle sensor to determine when the vehicle is turning in a tight circle. This condition causes the electronic control module to reduce torque to the rear wheels to prevent binding in the driveline. The electronic control module is always checking for this condition as well.}

_{Influences handling at moderate speeds. The AWD system is used to influence vehicle dynamics. Other manufacturers limit AWD to aiding traction or providing off-road capability. They concentrate on launching the vehicle or going off road at speeds up to about 25 mph (40 km/hr). Above that speed range, they use it to limit wheel slip for traction. Additional ECM calibration controls torque to the rear wheels for improved handling in the 25-65 mph (40-105 km/hr) range. In this speed range, the system utilizes torque to the rear wheels during cornering with the throttle open to make the car turn more easily – make the handling more neutral. This is more readily accomplished with an electronically controlled system, than with viscous-coupling or gerotor systems that require some degree of front-to-rear slip to transfer torque to the rear wheels. Above 53 mph (113 km/hr), the control strategy provides minimal torque to the rear wheels under normal driving conditions to aid fuel economy.}

_{Works with ESP and Traction Control the electronic control module also interfaces with the ESP and traction control systems. The interface allows the ESP system to use the ECC to help gain control of the vehicle. For this purpose, torque transmitted to the rear wheels by the ECC can be reduced. The AWD system is not traction control. It only works on situations where front-torear traction varies, for instance, front wheels on ice, rear wheels on dry pavement or climbing steep grades. AWD does not aid side-to-side traction. ESP does that through brake intervention.}

[outtahere]

I'm new to being on a forum and hope I don't tick anyone off by joining in here. It seemed to be the appropriate discussion to get advice from.. I am wondering if anyone has tried turning off the traction control for icy roads?

Background: the northern Alberta roads, especially highways go through several periods of extreme ice buildup because they don't use salt, instead some calcium product is used that results in a nice thick layer of ice. That would be another topic for up here! My Journey handles wonderfully on snow and a normal smattering of ice, but on this thick layer, gets "squirmy". Speed is not the issue. I have seen on the forums that people have brought up this issue, but usually get shot down for not driving to conditions. This is definitely the only vehicle that I have driven that has this feel to it. Just wondering what other people have done that have experienced this, and if turning off the traction 'button' helps if anyone has tried it. I feel that the issue is the AWD system trying to steady the vehicle.

[dhh3]

Welcome to the forum. I had the use of a Malibu last night and the only way it would go through my unplowed neighborhood was to turn off the TC, and rev it to about 4,000 in 2nd to make any headway. If I left TC on, it just wanted to slip to the curb. I have not tried this on the DJ yet. TC light does come on, but I have not had to turn it off yet.

The more I think about the AWD, I leaning to the side of FWD because I don't have all those extra electronics and weight. Winter has just begun: time will tell.

Edited January 14, 2015 by dhh3

[Lobitz68]

I'm new to being on a forum and hope I don't tick anyone off by joining in here. It seemed to be the appropriate discussion to get advice from.. I am wondering if anyone has tried turning off the traction control for icy roads?

Background: the northern Alberta roads, especially highways go through several periods of extreme ice buildup because they don't use salt, instead some calcium product is used that results in a nice thick layer of ice. That would be another topic for up here! My Journey handles wonderfully on snow and a normal smattering of ice, but on this thick layer, gets "squirmy". Speed is not the issue. I have seen on the forums that people have brought up this issue, but usually get shot down for not driving to conditions. This is definitely the only vehicle that I have driven that has this feel to it. Just wondering what other people have done that have experienced this, and if turning off the traction 'button' helps if anyone has tried it. I feel that the issue is the AWD system trying to steady the vehicle.

It would likely help... The car takes away power from slipping wheels, so it makes sense that you would lose power. Try it and see.

[B4ZINGA]

I always turn off TCS (as much as the provided button allows, anyway) driving around town. TCS sucks away the power going to a slipping drive wheel, so if conditions are especially slippery, you'll be standing still.

Note that turning off TCS turns on AWD. I turned TCS off a few nights ago, and managed a nice powerslide in an otherwise FWD vehicle making a U-turn on Woodward Ave. Opposite-lock was needed to control the slide. Very fun!

[2late4u]

ah good old woodward ave use to drag race there on fri or sat nights back in the early 70s

Edited January 13, 2015 by 2late4u

[jkeaton]

I had to turn traction control off to make it up a snow covered road in New York over thanksgiving. Otherwise, I would lose all forward momentum. The engine would not rev at all. As stated by dhh3, once traction control was turned off, I was able to get power to the front wheels and power my way to the top of the hill.

[outtahere]

Thanks all! I'll have to give it a try. Can't hurt - feeling the car trying to take over in weird directions is just a little unsettling!

[jkeaton]

Yes, you must be prepared to stay on top of it. It feels a bit unsettling but if your used to the sensation of the front end wanting to take off and correct accordingly, you will be fine.

[dhh3]

The way TC works is that it lightly applies the brake to the spinning wheel and thus send more power to the wheel that has traction, sort of like a LSD. If both front wheels are spinning, you do not want the brakes applied, and thus would turn off TC

I see that the AWD system shuts down on turns, to prevent binding. This would indicate to me that either the locking clutch or the rear end is not a differential. I'm thinking that the rear end does have a differential and the rear driveshaft becomes just a direct drive to the rear wheels. The 4x4 system was like this in my Nitro; but, I could turn it on or off with a switch. It electrically connected the 2 driveshafts, but the transfer case was not a differential like on a Jeep. I could see where this AWD set up would be handy on a quick start on solid pavement to prevent torque steer. I'm even experiencing a small amount torque steer when I apply the brakes.

Indiana is the land of the flat! I happen to be lucky enough to live in the hilliest neighborhood for miles around. So there is one hill that AWD would help me, but so far the DJ has been a trooper, even with the hill was not plowed. I attribute this to the weight of the V6 over the front axles. I have yet to turn the TC off.

[outtahere]

I'll have to dig out the manual. I tried pressing the traction button yesterday to see how it would feel, but it wouldn't work. My Journey is an automatic, so maybe it will have to be out of drive?

[Lobitz68]

No. Should be able to push it whenever...

[dhh3]

I've pushed it to see what happens. Light on the dash comes on until I turn it off. I have not needed it yet.

[Journeyman425]

You won't notice any difference under normal driving except that the amber warning light is illuminated all the time. When there is snow on the ground, try driving in an empty parking lot and toggle between modes. Mash the gas with the TC off and the wheels will spin freely as they lose traction. Turn the TC back on and you'll hear the ABS pump and feel the vibration as the system tries to slow the wheel speed to match the available traction.

Edited January 17, 2015 by Journeyman425

[dhh3]

Oh, what fun. Now, I'm looking forward to the next snow!

[dhh3]

Around 6" of snow, with more to come. My addition seems to be one of the last to be plowed, but should be closer to the top because of the hills. DJ took me out of my garage (backed out) and up the hill in R, without a hint of anything being different. I was considering backing it into the garage, but decided to take my chances. Put it in D and she just went like nothing was wrong. TC came on a few times, from a complete stop, on a plowed road with slush, but saw no reason to turn it off as it is acting like an ELSD would. So, my concerns seem to be unwarranted. I was concerned about leaving an unplowed road into a plowed road, where the snowplow will leave a mound of snow to drive though. Not an issue, but I could see that if this mound was high enough, I could possibly get hung up, but so far, so good. I'm beginning to see that I did not need the AWD. Thanks to everyone who replied to this thread. I have learned a lot.

But, winter isn't over yet, now is it?

Edited February 1, 2015 by dhh3

[JourneyMan71]

I had a 2014 FWD Dart, I really loved it in summer and fall. Then winter came and last month we got 8+ inches of snow and my street was so bad, I had to park at the end of my street a walk to my house. A fwd Journey is fine, but I wanted/needed that extra wheels spinning to help me deal with the kind of snow we get in NW Ohio. Besides it only goes AWD when traction is needed. MPG's only take a 1-2 MPG hit for AWD, IMO to me it was worth the cost and a small piece of mind. Tires are another great way to get through the snow/ice as well.

[2late4u]

i have fwd only and was driving in some real bad ice and sleet last week and was going about 40mph and for the first time the wheels started to slip and the traction control kicked in and the light came on seamed really weird for me and wasn't sure what was happening to the journey so i reached over and pushed the button to disengage the traction unit and had no more problem. so i tried it again and the same thing happened and so i disengaged it again. now this is the first vehicle i've had that had this option and to be honest i really didn't think much of it,seemed to be more trouble than it helped. but as i lived in the north and was use to driving rear wheel drive in the winter then started using fwd for the last 20 yrs, i wouldn't buy a awd vehicle for myself....

[briandf]

I live in Ft Erie Ontario [across the river from Buffalo] and just bought my '11 Journey R/T AWD. Am looking forward to seeing how this bad boy handles the winter roads here. I'm not worried about it, since I am a semi retired trucker and former snow plow driver. Snowy roads are just a distraction for me.I get more angry with other drivers who should stay home in a storm, though. Now that I am getting older , I decided to trade my FWD Impala sedan for this SUV for the sake of comfort and safety. Getting to the idea of using 2 snow tires, BAD idea for anyone.. in fact, it is illegal in Ontario for a tire shop to mix winter and all-season treads, for obvious safety reasons. Kind of like wearing one bedroom slipper and one winter boot when you go out. Not smart, ever. Use the same type tire for all four or either type.

[Lobitz68]

Getting to the idea of using 2 snow tires, BAD idea for anyone.. in fact, it is illegal in Ontario for a tire shop to mix winter and all-season treads, for obvious safety reasons. Kind of like wearing one bedroom slipper and one winter boot when you go out. Not smart, ever. Use the same type tire for all four or either type.

While I agree that it doesn't make a lot of sense, it isn't any less safe to mix tires... Although if you are only doing 2, they should be on the back tires from what I've read and heard from "tire guys".