Dirty transmission fluid or clogged transmission fluid filters can cause transmission shutter so check your transmission fluid to see if the fluid is clean and not dirty or burnt.
Another common cause of transmission shudder is a failing torque converter and if the torque converter is bad then the transmission will have to be removed to replace the torque converter.
Just like changing your engines oil the transmission fluid and filter should also be changed at recommended intervals to prolong the life of your vehicles transmission.