The line that goes through the hull from the fluid box to the drive popped off in the water n lost all my tranny fluid n won't kick in n outta gear ... Assuming no fluid is the problem with that but is there any thing I need to flush the drive or the tranny with to make sure there's no water in the system ?

From the fluid box to the drive should be (Merc Gear Oil) not tranny fluid. Even if hose popped off, it shouldn't drain the drive itself. If you have Tranny Fluid in the bilge it is not from the hose, if you are describing it correctly. Nothing from the transmission goes through the hull into the powerleg of the drive.
Need more info, possible picture

Ya your right I just realized that was a drive oil tank not tranny fluid ... Ok so any ideas why its not engaging in drive or reverse ?

Keep it simple, is the throw of the transmission cable allowing it to fully engage the transmission? I would disconnect the transmission cable. Start the boat on the hose. And manually put the transmission into gear. If it then engages it needs a cable adjustment. Make sure the transmission has F type transmission fluid, that it is the correct amount, not over filled.

What tranny do you have?

Borg warner trans I believe ... It always worked before but i had to replace the ujoint shaft and bellow ... I'm gonna mess w it tonight hoping its just fluid level or an adjustment like you guys say . N type f fluid , how many qts by chance ?

Sure it's not one of the tranny cooler lines your having a problem with?

Replacing the U-joint is part of the drive, if you pulled the drive off, and reinstalled it, are you sure you got the drive shaft into the transmission?????

Drive won't go all the way on if the shaft doesn't go into the tranny.