need help loosen the shaft nut of my new turbo because the rear nut in the
shaft it's grinded.

It's posible put the the round part betwen the nut and the propel in a vise?

all the turbo's i've worked have the nut tu put a wrench.

 

the rear nut in the shaft is grinding? post a pic of the issue so i can see it for myself.

 

the grind marks are where its been ballanced by the manufacturer...chech the compressor nuts not a left hand thread...should be ok in a vice ,try not to mash it up tho cos it will throw the ballance off..make sure you scribe a line from the comp shaft to the nut to the impeller and line it back up when rebuilding