Any possible fixes for separated mending plate in truss?
Gently remove the old plates and jack or screw the bottom chord tight, then install steel plates with screws. Don't trust the original gussets to hold if you pound them back into place. The new plates should be at least as large and thick as the originals.

1&quot; truss-head screws would be appropriate. Put screws in every hole with good wood behind it.