GM states to never use an impact gun, air or electric, on the axle nut!! And to never reuse that nut! Hand tighten then torque to 155 ft/ lbs.
I always retorque the nut after a 10 mile drive!
But if the clunk is gone great!

 

MY torque wrench goes to 150 foot pound and I may make a wild assumption that yours is maxed out at 150 as well. If I even needed to, I would tighten until torqued at 150 then I would pull just that little bit harder. Over torquing that nut can put alot of strain on the driving components. Be careful!