Car wont go into 3rd gear please help

Hey, i have a 2000 Crown Vic Retired police interceptor, 130k.
It won't go into 3rd gear, my mechanic said it was the Tourque Converter? Can anyone give me feedback on this issue. thanks.

A torque converter shouldn't prevent the car from going into 3rd gear. Are you sure it's 3rd gear it won't go into and not the engagement of the torque converter lockup clutch?

Does the OD band lock up skipping 3rd gear? Any stored codes from the transmission or ECU?