8 3/4, (741) Pinion seal removal

I am switching our my 3.55 to my 2.76-i red the posts on marking the nut an all-the chunk is out-what is the best way to secure it to losten the nut (torque is 400+ pounds). I know many of you have done it before. Can I use my air tools if I am very carful (lostening nut only). Thanks

Dave