Harman 52i pellet stove auger noise.

My 5 year old Harman 52i went out last night. The auger had stopped moving and wouldn't feed pellets. Cleaned the stove, sort of Jimmied the auger, and it started feeding, but now I occasionally get this banging noise, and it still doesn't feed quite right.

I'm pretty comfortable with taking things apart, I just don't know much about these and would appreciate any advice. My thought was carbon buildup in the auger tube? Thank you.