Rep Power: 193

i have a 99 civic ex
5speed and it has bad main seals and i was taking the tranny mount off to put new clutch and this nut unscrewed the bolt instead of it self and a metal peice fell off

CAN I FIX THE SOME HOW OR NEW TRANNY CASE

 
Rep Power: 285

I forget what type of metal the tranny case is made out of, but find a good local welding or fabrication shop and they should be able to weld that piece back on for you and re-tap the hole. I wouldn't go to a regular mechanic, try to find someone who specializes in welding.
I hesitantly say you might be able to repair that with JB Weld, the bottle says you can repair cracked engine blocks, but I wouldn't attempt it.

Also, change those bolts out for some new ones, those ones look like the rust is pitting so they're at the point where they will start to strip easily. Its a simple change, that will make future repair much less likely to end in something like this.

 
Rep Power: 193

so thats all i can do and does anyone know the tranny case metal type

 
Rep Power: 812

i think its aluminum? yeah welding is really the only solution for a hi torque bolt area. jb weld would snap right off. if you were just gluing it for a bracket it would be okay, but not an engine mount.