  The threshold transverse response functions R_T(q,omega) for 3He and 3H are
calculated using the AV18 nucleon-nucleon potential, the UrbanaIX three-body
force, and the Coulomb potential. Final states are completely taken into
account via the Lorentz integral transform technique. Consistent two-body pi-
and rho-meson exchange currents as deduced using the Arenh\"ovel-Schwamb
technique are included. The convergence of the method is shown and a comparison
of the corresponding MEC contribution is made to that of a consistent MEC for
the meson theoretical r-space BonnA potential. The response R_T is calculated
in the threshold region at q=174, 324, and 487 MeV/c and compared with
available data. The strong MEC contributions in the threshold region are nicely
confirmed by the data at q=324 and 487 MeV/c although some differences between
theoretical and experimental results remain. A comparison is also made with
other calculations, where the same theoretical input is used. The agreement is
generally rather good, but leaves also some space for further improvement.
