So, I noticed it was getting harder to pedal as if the rear wheel is being squeezed by the brake even though it's not. Upon more pedaling, I can hear a loud squeaking sound, I tried to listen intently to see if it's from the rear wheel bearing or the motor, it seems to be coming from the motor, appears to be from the clutch drive sprocket. I think the drive sprocket is having trouble spinning thus causing the drag, when I get off the bike to push it, the wheel would be hard to turn and would lock up upon a few rotations. My question is......what can I do to remedy this? Would adding more grease cure it? Or is it something else, like inside the motor?!