I have a damaged flexplate on my 1998 LS1 Trans Am, my question is do I need to drop the autobox to change the flexplate or is there a quicker way?

 

Yes you need to drop your automatic transmission to replace the flex plate but first you need to unbolt your torque converter from the flex plate.

Your flex plate will be bolted to your crank.
Your torque converter will be bolted to the flex plate.
Your torque converter is on the input shaft of the transmission which bolts to the block by the bell housing.

 

Yep, must drop. Something i hate doing in an fbody.