  The weak $N-\Delta$ axial-vector transition amplitude $<\Delta| A_{\pi
^{+}}^\mu |N>$ - important in $N^{*}$ production processes in general and in
isobar models describing $\nu_\mu N\to \mu \Delta$ processes in particular - is
examined using a broken symmetry algebraic approach to QCD which involves the
realization of chiral current algebras. We calculate a value for the form
factor $C_{5}^{A}(0)$ in good agreement with experiment.
