While we're at it (seeing how my totalled '08 135i has now morphed into a '13 135i) I've been looking for info on the gearbox and ran across this PDF - looks like lube is specific based on a plate located on the flywheel for those who have manual GS6-53BZ gearboxes:
http://www.thectsc.com/images/pdf/teml11.pdf
And, of course, the 2013 has a down rated (torque capacity) GS-45BZ : -(
The ZF site sez the S6-45 takes up to 470 NM of torque and the S6-53 up to 600 NM:
http://www.zf.com/corporate/en_de/pr....shtml#tabs1-1
And one more link:
https://ci-portal.zf.com/global/medi...s/TE-ML_11.pdf