Have your account information, including both your account and card number, handy before you attempt to contact TCF customer service.
Contact customer service, or head into a local branch. If you decide to call, you will be asked to verify certain information, such as the address and phone number linked to the account. You will also be asked to provide either your account number or card number and your social security number. If you decide to reset your password in person, a valid ID card and your bank card will likely suffice.
Write down your new PIN in a safe place. Do not share it with anyone or display it anywhere that it could easily be read.