Pinion nut is 33mm across the flats and the hex part is very shallow. You'll do less damage to the nut when you remove it if you face off the internal bevel of the socket before applying force to it. Thread is left hand as others have said, and unless you really want to get involved in setting up the pinion shaft preload, carefully scribe the nut and pinion shaft so that after the old seal has been replaced the nut can be tightened to exactly the original position on the shaft, the actual torque required to do this does not matter, it's the position on the shaft that matters. This of course assumes that Quaife/Morgan got it right in the first place!😃🤔