If this noise appears to be emanating from the Drive Motor, it could indicate a problem within the motor. This component cannot be serviced and will have to be replaced if the noise is unbearable.
Noise could also be indicative of a problem within the Exhaust Fan Motor. This usually occurs when the fan motor bearings have reached a state of excessive wear. You can attempt to move the motor shaft by hand. This motor is fixed in place and should not move. If it does move, it is bound to generate noise during its normal operation. The motor bearings cannot be repaired or lubricated, and the motor will need to be replaced. Similarly, the fan motor and blower motor should be checked to ensure that their bearings have not failed.