I think it's a 1 13/16 3/4 drive socket.
I also bought a 1/2 to 3/4 adapter so it would work with my 1/2 drive torque wrench and breaker bar.
Used a 6 foot length of pipe around the breaker bar to undo the 210 ft lb nut.
Add a heat gun to heat any races that get stuck in there and a 3 arm reversible puller made the job quite easy. Make sure your torque wrench can exceed 210 ft lbs.
Of course, dont forget to unstake the nut before you try to loosen or you'll bend the breaker bar.
Ramon
1994 540iA Nikasil EAT Chip
Tampa Bay, Florida USA