The two‐dimensional model introduced in a previous paper to describe the nematic phase of rodlike polymers is used to obtain predictions of transient rheological response at high shear rates. First, the transient behavior of a single domain is considered. It is found that, between the tumbling and nontumbling regimes, an intermediate range of shear rates exists where the director continuously oscillates between two orientations close to the shear direction, a result independently obtained in a recent work by Larson, who has considered the full three‐dimensional case. Polydomain structure, typical of polymeric liquid crystals, is then considered. In this paper, results for this case are given for the nontumbling regime only, whereas the tumbling and oscillating regimes are considered in the next paper.