2013 XC90 Alternator drive gear bolt torque HELP

[eloteman187]

I have the issue where the bolt on the READ side gear/pulley that drives the alternator came loose. I have a new drive gear but I notice that when tightening that I am just turning the rest of the READ system and the serpentine accessory pulleys. How do I hold the gear so that I can torque it down?

The gear I am trying to hold to torque: https://usparts.volvocars.com/p/Volvo__S60/Clutch-Gear-Transmission/42902372/30750136.html