Diagnosis
That's almost certainly the pickup roller assembly. The rubber rollers get hard, shiny, and lose grip, then the gears grind as they slip. Yeah, this one's common.
How to Fix It
You need to replace the feed roller kit (Canon part RM2-8038-000). Power off and unplug the printer. Open the rear cover (the face-down output tray). You'll see a green lever—lift it to release the whole pickup assembly. Slide it out. The rollers swap out pretty easily; they just clip on and off the metal arms. Put the new ones on, slide the assembly back in until it clicks, lower the green lever, and close the cover.
If That Didn't Work
If the noise persists after new rollers, the sound might be coming from the separation pad (a little friction pad next to the rollers). Debris can get under it. Take the assembly out again and check the pad for paper dust or wear.
Heads Up
Don't try the 'rubber rejuvenation' trick with alcohol or sandpaper on these rollers. The coating is specific, and you'll just make the feed issues worse. The replacement kit is cheap and lasts years.