How much should it cost to replace the 2 shift solenoid valves on my malibu? on 2004 Chevrolet Malibu

Auto zone ran a check and said its the shift solenoid valve....and that if one is out I may as well have both replaced. Any idea on a guestimated cost for this to be done?

Asked by for the 2004 Chevrolet Malibu
approx cost is 400.00 parts and labor. but have circuit ck'd 1st it could be an internal issue