I am trying to remove the ECM from the plastic tray on my wife's 08 Deluxe. The 4 allen drive screws just turn and turn without coming out. Am I missing something completely obvious? This ain't rocket surgery!

 

Sounds like you have nuts turning on the back side.

 

There are no nuts on the backside. It looks like there are some small threaded inserts in the plastic, but they just turn with the bolt. They are round so there is no way to hold onto them. Besides, they're flush with the back of the tray. Trying some penetrating oil now. We'll see.

 

If the inserts are turning in the plastic you're going to need a new ECM caddy. It is not uncommon for the lock patch the factory put on the screw to be stronger than the bond between the insert and the caddy.