<br>I got stuck in the snow yesterday!!! :(<p>Fortunately it was right in front of my house, so the neighbor and my two brothers helped muscle it out of it's jamb.<p>the thing is that while it was stuck I had my brother check out which wheels were spinning... only the rear passanger and front driver side where spinning while it was stuck. <p>Somehow I always thought that all the wheels would spin in such a situation. I'll ask the dealer about it next time I go.<br>

If all four wheels spun, you'd be in serious trouble. The A4 has three TorSen differentials that divide power... remember that TorSen senses torque and resistance. Torque and resistance give you an estimated amount of drive friction available at each wheel, but TorSen doesn't calculate traction -- it only locates resistance and pushes. When it pushes too hard, you get wheelspin. When it doesn't push enough, one side of the propellerset in the viscous coupling rotates without sufficient power transfer to torque the wheel. The condition you describe is not rare, it took a solid fifteen minutes with some serious burning smells and overrevved clutch release to get Cathleen's car out of a snowbank in Detroit after the snowstorm. But Quattro worked, and slamming first and reverse until something happened worked. Rolling momentum is your friend in these situations, not overloaded couplings that have good rates of efficiency but bad rates of relevant power transfer -- the relevant variable in a "my A4 is stuck" scenario.<p>Nothing is wrong with your car, but a number of things are wrong with your understanding of the mechanical systems involved and your resulting driving choices when behind the wheel. Read up on Quattro before trying to utilize it.<p>Cameron<br>

First: There are ONE Torsen, and TWO open differentials!<br>Second: There are NO viscous couplings!<p>The Torsen splits torque between the front and rear axle. And the open differentials splits between left and right. The scenario described by Mathieu should not have happened, since his A4 should have the EDS system (Electronic Differential Block).<p>Without EDS you are likely to get stuck in situations like this. This is because the open differentials (i.e the ones without diff blocks) even out the torque between left and right, and since one of the weels are in a free slip conditions, the diff transfers all the force to the slipping wheel. Note that since both a front wheel and a back wheel are slipping, the torsen is working as it should! If there were an open diff instead of the torsen, the car would be stuck if only one wheel lost grip! Now.. the EDS should have applied breakforce to the slipping wheels, those allowing the open diffs to transfer more power over to the wheels not spinning. I can't tell you why it wasn't working, but iether you have overloaded the EDS (It cuts out after extensive work to prevent overheating of the breaks) or you might have some fault in the EDS/ABS system. If it was overload, you would just have to wait for the breaks to cool down. <p>In Europe all Quattros have EDS, and I would be surprised if that wasn't the case in North America/Canada.<p>Regards,<p>Fritz<br>

thankx for clarification on the torsens etc. i are dead on.<p>However:<br>i think it is possible to overpower the EDL before they cut out. I noticed in deep snow (my alley way every day, the undercarriage scrapes) if i really gun it, i get wheel spin. Plus smell of brake pads later.<p>I wonder if upgraded brakes would benifit EDL?<p>Comments?<p><br>1996 a4 2.8 qm<br>

The EDL allows wheelspin if all the wheels are spinning equally fast! Remember, it is not an antispin system.<p>Since the EDL is cut after a certain amount of load, independent from the temperature of the brakes, it's function will not be better with upgraded breaks, but they are sure to handle the force from the spinning wheels better.<p>Regards,<p>Fritz<br>