It will come off without removing the engine. It is kind of a pain in the a$$. Basically you pull the shift shaft with the cover. Factory Pro makes a detent kit to improve the shift feel and describes the procedure pretty well.
Here-
http://www.factorypro.com/Prod_Pages...3.html#Install Notes
Go down the page to the detent kit and click on install notes.
BTW, I've installed the detent kit and it does make the shifting more positive and snappy. Pretty much an all day affair removing the cover, replacing the kit and replacing the cover.
Have fun!