Help 5spd stuck in reverse (Read)

[WMowat]

I lost my 5th gear a couple days ago...... Bought updated nut removed rear housing and replaced. I tightened the nut really tight,, I didn't have a proper socket so I tightened it with a air chisel... Got it all back together today and went for test drive, drove about 100 feet and then a awful grinding and screeching noise, locked up the back tires and almost stalled the engine. Tried all gears and all fwd gears are like there jammed, but reverse still works. What the heck happened ? I installed the gear the right way, It was in perfect shape. What might have happened ?