Replacing the friction disc is pretty straight forward. Depending upon your two-stage snowblower model (most of them follow the same basic design) you will need to remove the bottom plate that covers all of the internal drive components. Tilting the snowblower to the front makes this job easier.
Remove the right side wheel and move the drive shaft out slightly. The friction disc should slide onto the shaft easily. Just tighten down the friction disc bolts and reassemble.
This entire procedure was completed in 15 minutes.
For reference, this replacement was done on a late 1980’s/early 90’s Craftsman 5hp/22″ two-stage snowblower.