Transformation methods are used to calculate the second-order contributions to the effective hamiltonian of a D(T₂) ion coupled to E-type displacements in a cubic crystal. It is found that it is only possible to relate the first- and second-order Jahn-Teller reduction factors when a cluster model is used. For other lattice models, the parameters are unrelated. Finally, the orbital contribution to the magnetic susceptibility of a crystal containing delta (T₂) ions is calculated.