The response of 3He–A textures to imposed superfluid massflow and applied magnetic field is studied by means of numerical integration. Results are presented which indicate the existence of a previously unsuspected textural phase transition under increasing magnetic field in massflows of strength comparable to that of the dipolar interaction. This transition is from a stable dynamic domain-lattice texture to an unstable texture, and is identified by the dramatic change which occurs in the Fourier transform of the time charactristics of the texture. In higher magnetic field a dynamic domain-lattice transverse to the axis of the low field texture becomes the stable textural phase.