I'm facing a pretty large snowfall (6") and a car that is in the garage frontwards. Wondering if AWD works in reverse. I'm going to shovel in any case but might do a little less if I knew AWD works in reverse.

 

Yes

 

Good info - I did not know that. Perchance does AWD work if your foot is not on the accelerator? I'm guessing not.

 

Seems to me that Audi's quattro AWD system, which uses a Torsen center differential, is a gear-based system which distributes the torque between front and rear axles. As such, AWD is permanently active. As long as the engine is supplying torque (foot on the accelerator or not), AWD should be working.

But I'm not an engineer, so somebody may dispute this.

As a side note, I have learned that quattro also allows engine braking to be applied equally to all four wheels upon deceleration. Nice.
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Of course AWD works in reverse. With the center differential quattro, the two axles are permanently connected via center differential. Torque distribution is a different story, though. The open differentials in the front and rear can only receive as much torque as the wheel with the least traction can put to the ground times two. That's why EDL is required. EDL will apply the brakes to the spinning wheel to direct additional torque towards the wheel with more traction. The center differential on the other hand is self-locking, so based on available traction it will direct torque to the axle with more traction. The one issue you might have going in reverse is that the front can only receive up to 70% of the torque w/o ESP help whereas the rear can receive up to 85%. When you are going in reverse than the weight of the car shifts to the front axle, so you'd want to maximize the torque going to the front axle, however, the rear-biased setup is optimized for driving forward. You could have more difficulty making it up a hill in reverse versus going up facing forward. Some A4s have quattro ultra. In this system the front wheels are the primary driven wheels and the rear axle is decoupled if the system thinks AWD is not needed. But this system also normally engages the rear axle proactively when starting from a stop as it is very likely the car will benefit from AWD to get moving. Quattro ultra is forward biased, so it can send more torque to the front axle than the rear axle, so you might get up a hill easier in reverse.

 

Ha! I have the same situation here in Illinois. I have a large drift outside my garage on the driveway. I am going to try to use the A4 to drive through the drift and exit my driveway. I have winter tires and I am still amazed with the control and traction that Quattro provides.

 

Also if you have the sport diff, that works off throttle as well.