I don't hear anything on my '18 other than the occasional tick, tick of the fuel pump regulator. In fact, multiple fuel pumps on the AWD gen2s where the saddle bag shaped fuel tank straddling the rear wheel drive shaft requires fuel shifting from one storage side to the fuel feed side.
But a rotary mechanical noise like a spinning motor could be the auxiliary vacuum booster pump for the power brake unit. Many engines e.g. Ford/GM cannot provide sufficient vacuum reserve for operation of all brake related functions at all times under all motor condition, e.g. prolonged anti-skid application, where vacuum reserve may not be adequate so the use and electric pump to supplement vacuum. The 70's era Fords used a sealed empty metal 16 oz. "soup can" to supplement their power booster and vacuum operated HVAC controls, reservoir now replaced with a high tech $50 -$100 electric vacuum pump.
Current Chevys -'19 Silverado RST;'18 Malibu LT Redline;'18 Traverse Premier Redline<br /><br />Previous Chevys:16 Silverado LT;16 Malibu LT2;'17 Impala;'16 MalibuLT;'15 Camaro LS;'15 Traverse; '13,'12 and '07 Avalanche LTs; '11 Tahoe LT; '13 &'11 Malibu LTs; '08 Trailblazer;'06 Colorado WT..... Chrysler era.....'80 Citation;'75 Impala;'72 Chevelle;'69 Camaro R/T;'65 Impala SS;'62 Nova