The elastic constants and electrical transport properties of single-crystal Gd and Gd–Y are measured for Y≤26 at. %. There are clear features in the elastic constant C33(T) and in the temperature derivative of the a-axis resistivity, dρa/dT, at the accepted ferromagnetic Curie temperature (TC), and at the accepted spin-reorientation at TSR. In the Gd-rich Gd–Y, there is a third feature at T* below TSR, which is consistent with evidence for a further second-order transition. A modified magnetic phase diagram for Gd–Y is proposed. © 2003 American Institute of Physics.