Hello I will help you with your question,
AAmco is quoting you the complete job that is sure to repair the problem and stop the code from setting.
This trans can be rebuilt if needed but the usual cause of the torque converter code (P0740 or P0741)? is the solenoid on its own. The solenoid can be replaced for 6 hours labor and $100 in parts so that is a far cry from the $2300??? they are quoting to do the bushing as well.
It is taking a chance but the solenoid can be electrically measured to see if it is actuating, if it is not it is a sure bet that just replacing the solenoid will fix the problem.
It is up to you if you want to take the chance and only spend the $700 to see if that fixes it..
Let me know what I can do ot help you with this