I wouldn't think there is a lubrication point.
The auger system is rather simple. The motor/gear assembly rotates tha auger. I would start by emptying all of the pellets, then try rotating the auger forwards & backwards listening for the sound you are
hearing. It shouldn't be as loud but the same. If the sound is present it is most likely the connection - motor to auger. If none of this proves out, start the pit concentrating on listening to the auger motor.
if the sound appears it is most likely the motor gearing. In that case the motor assembly should be run independently from the auger & checked again for noise.
Before you do any of this you may want to contact Cookshack with the S/N in case they need it, and ask about this issue.