This morning my truck started making a slow knocking/tapping sound from the front of the transmission. It started while sitting in the wataburger drive through. After continuing to work it quietened down but is still there. I am not positive it is from the trans but sounded like it when I crawled under it. My thoughts were maybe front pump busted or torque converter. Please help with any insight to problems similar that others have had. I work as a Toyota technician but have not heard a noise like this one before. It does vary with rpm in all gears including park and neutral.