Okay now i get
torch.Size([1, 1, 384, 384, 384])
torch.Size([1, 384, 384, 384])

from the prints.
I forgot unsqueeze before. To expand you need too
    predicted_model[0].unsqueeze_(0)
    predicted_model[0].expand(1,1,384,384,384)

in case someone has the same problem.
Somehow, now i run into this error:
IndexError: Target 1 is out of bounds.

Might this happen because i just changed the size without passing values there?