About 8 months ago took me 3 days of frustration, fearing the worst, thinking that it would never come out. It eventually came.
Just be persistent as mentioned, keep spraying penetrating oil you will get there.
I just removed the thruster again this week for new gears, it was out in 30 minutes.
Tonight I shall be reinstating the unit.
Can't wait to test it with new gears and prop.