Hi please note the following process for passport renewal.
Get to the indian consulate webpage, apply for new passport application online.
You will see an appointment time and date upon completion which you must ignore, you can only visit them after three business days. If you go earlier, they will send u back.
Print the completed application form, fill in the remaining fields. You need this form to enter the consulate.
Have all the necessary documents in tact and ready. The person at the reception will check all the forms and then only will allow you. If not he will send u back. Esp with the photographs measurements.
Upon sucessful application, they will give u printed receipt which will give u approximate time and date to collect your new passport. (10-12 working days). You can even give them a self-addressed envelope for getting it via mail, but I have heard lots of stories of many who have not received their passports via mail.
If u need any other detail keep me posted.
Chicago Indian consulate customer service is really bad, they never treat you with respect and will easily insult you so be prepared.