2000 Evinrude FICHT 225HP Lower Unit

[bassgunner]

I've torn up my lower unit, but I'm not sure how bad!   I've busted a gear set before and was in the position to run the trolling motor back to the ramp.  Unfortunately, this time around I was on the North Landing River 20 miles down river with a falling tide. 

Well, to make a long story short...I'm running back up the river WOT and I hear a knock in the gear case.  I throttle back down and shift to neutral, the knock goes away.  I shift to reverse, the knock comes back.  The knock is rythmic versus sporadic and is present only when the prop is engaged.  I made my way to a ramp running at idle until the gears finally went and I lost both forward and reverse. 

:-\Here's my question...can my lower unit be salvaged with a partial rebuild, or did I send it to the grave?

Any help is greatly appreciated!