Quattro all wheel drive question

[Brooklyn67]

Hi,

I have a '02 S6. I was driving up a semi-deep snow filled driveway last night (12"-15" of snow) and was doing fine until there was a dip in the driveway where the snow was deeper. The deeper snow got under the front of the car so that the front wheels couldn't drive forward and the car stopped. I tried reverse, but the car was stuck and I could hear the wheel/wheels spinning - unable to get traction.

This morning, I came back to the S6 to see the front end elevated, since there was a good deal of snow underneath it, but the back was sitting on the ground with normal wheel to fender clearance. After removing snow from behind all the wheels, I tried to back it out (a friend of mine came by and plowed all around the car), but it wouldn't budge. I noticed that only the passenger, front wheel was spinning when I put the car in reverse (this is the corner of the car most elevated by the snow...so, with the least traction), but the other wheels that seemed more planted on the ground were not moving.

My understanding of the Quattro system is that it will and can transfer drive power to the other wheels that are not slipping. I've never had an issue with my S6 in any weather conditions. Also, the ASR light is blinking on the dash - so the system does know that there is wheel slip and the e-gas system is slowing down wheel spin regardless of how much gas pedal I input.

So...can someone help me understand why the other wheels are not turning or if there is an over-ride that I can input to lock the car into 4 wheel drive?

Thanks.

[studioRS]

My suggestion would be to press the ESC button on the dash and try that first in forward and reverse. Obviosly if you are high centered don't continue spinning. There is not much you can do once you're high centered on snow to get the quattro system to work. Once you get the packed snow underneath removed and with the ESC toggled off — hold on!

I prefer to drive in the snow with the ESC off, much better control with no computer intervention. All my past 9 Audi quattro's have been 5-speeds and only my last S6 had the Torsen center diff. Man I miss the days of my ur-quattro with manual locking diffs. Last nights drive home from work over the mountain was a total drift rallye stage!

[Scotty@Advanced]

Your S6 has open diffs in the front and rear and a torsen center.

Torsen's when experienced with near zero traction behave like and open diff, so in essence you only have one wheel drive. This behavior is normal.

[Brooklyn67]

Thank you for the quick comments.
Turning off the ESP was right on...plus continuing to remove or loosen up the packed snow under the car that was lifting it up.
I was able to get it rocking and there was more drive from both the front and rear wheels....and it plowed out in reverse.

I was also just thinking about wishing it had a 6-speed and the old days of locking hubs...
Granted, with the ESP off and the transmission in "D", it felt like old '70s American Muscle with posi-traction...;)

Thanks very much again.

[Racin2redline]

Your S6 has open diffs in the front and rear and a torsen center.

Torsen's when experienced with near zero traction behave like and open diff, so in essence you only have one wheel drive. This behavior is normal.

When I feel I have enough money for disposal this is the shear reason I'm getting a wavetrac rear diff ;).

Shoulda bought an allroad, mine woulda beasted straight through that. It's also much easier to modulate power when you have a manual transmission

[Brooklyn67]

It's also much easier to modulate power when you have a manual transmission

Amen to that!

[JediJoker7169]

Thank you for the quick comments.
Turning off the ESP was right on...plus continuing to remove or loosen up the packed snow under the car that was lifting it up.
I was able to get it rocking and there was more drive from both the front and rear wheels....and it plowed out in reverse.

If you're ever stuck like this again, in addition to turning ESP off, you can also try a light application of the brake in combination with the throttle to apply load to the lifted wheel, thus allowing the Torsen to do its work and send some of the torque back where it's useful. This is especially easy in your car, given that you have an automatic transmission (left foot on the brake). This is what the rear EDL (electronic differential lock) does using the ABS system to simulate a mechanical LSD.

[19dabeast85]

Not sure how the s6 works but on my AR, according to the manual, when esp is disengaged EDL is activated. With ESP in its normal intervention mode you have what Scotty described...essentially one-wheel drive due to the open diffs and inability of the Torsen to multiply by zero. With ESP off and EDL activated the system will apply brakes to the spinning wheels to transfer power to the non-spinning wheels. This loads the corners with traction plus gives the center torsen something to multiply. I recently took my AR on some pretty muddy logging roads and for 10 minutes the car was constantly clunking/groaning as the brakes were being applied to different corners. EDL works and it's amazing how quickly it responds! That being said, one day I'm ordering a new TDI 01e with wavetrac and wavetrac rear diff from Scotty. I don't like depending on electronics to keep traction to the ground!

[Brandon002]

I had the same thing happen a few weeks ago. I was driving and had to swerve to avoid an idiot that was in the wrong lane. I drove into the piled snow on the side of the road and it got under the car enough that all wheels just spun.

After about 4 bags of salt, 30 minutes of shoveling, turning the ESP off and a lot of pushing we were able to get it going again. Makes me want to install a lift kit next winter. I have an A6, definitely wishing I bought an allroad with the snow we got in Chicago the past 2 days.

ESP is only good when you're moving or in light snow etc... any time you get stuck turn the system off.

[SamuelWest]

Same happends to me, got stuck here, only left front tires were spinning the others were still and the esp was off, så next time i should apply a little brake with left foot? it´s a automatic

[Racin2redline]

Yeah jabbing the brakes while pedaling the car steadily will help transfer the power back to the rear wheels.

[SamuelWest]

Yeah jabbing the brakes while pedaling the car steadily will help transfer the power back to the rear wheels.

Ok, will try it next time..if there will be one ;)

[JediJoker7169]

Yeah jabbing the brakes while pedaling the car steadily will help transfer the power back to the rear wheels.

I wouldn't advocate "jabbing" the brakes, but rather a light, consistent pedal pressure. Yes, you'll burn up the brakes a little, but it's easier on the drivetrain to have consistent resistance rather than delivering a series of shocks.

[mykcuz]

I find that if neutral drop from red line, I get instant traction.