Jem90

low speed, full lock, dragging feeling? is it because its 4x4?

moto-one

No, your dragging down the power by running the power steering pump up on the bypass.

glidar

Rumble during low-speed turns seems to be characteristic of quattro.

downindenver

rumble == torsen

glidar

there's a speed differential between the axles.

Bobby Kinstle

Its because the torsen has no moving parts under normal traction conditions.

glidar

Sure, but when there is differential motion, what causes the rumble?

downindenver

But in all of the torsen equipped Audis I've owned since I had an '88 90 quattro, the driveline makes the rumble when under power in a tight turn (making a u-turn, for instance). It won't make noise if coasting. I've found that unique to Audis - coincidently they were also all equipped with torsen center diffs.

If you trace the path the wheels make in a tight turn, the front-rear distance covered is very different. I *think* the noise you hear is the torsen distributing torque to wheels that have full traction.

I think this was explained in great technical depth waaay back on the audifans mailing list.