2002 Mitsubishi Montero Torque Converter

Hello,

My friend has pulled my motor out of my Montero Sport. We are now having extreme difficulty with socket size to remove the torque converter. They are thinking they need a 16 1/2 socket because the 16 is to small and the 17 is to big? Can you help? Is this true? Where do I get such a thing?

Thanks, Michelle