Equipped with shovels, gloves and boots, Auburn Gresham residents were working to manually unblock a sewer drain Saturday night as heavy rain and severe flooding put a damper on 4th of July festivities throughout the city and suburbs.Parts of the city saw as much as 2 inches of rain leading up to fireworks displays that were set for Saturday evening, according to the National Weather Service.The heaviest rainfall in Chicago largely fell south of…