  We present a new determination of the $N\Delta$ axial form factors from
neutrino induced pion production data. For this purpose, the model of Hernandez
{\it et al.} [Phys. Rev. D76, 033005 (2007)] is improved by partially restoring
unitarity. This is accomplished by imposing Watson's theorem on the dominant
vector and axial multipoles. As a consequence, a larger $C_5^A(0)$, in good
agreement with the prediction from the off-diagonal Goldberger-Treiman
relation, is now obtained.
