  Recent asteroseismic studies have revealed that the convective core of
$\gamma$ Doradus stars rotates faster than their radiative interior. We study
the development of differential rotation near the convective core to test
angular momentum transport processes that are typically adopted in stellar
evolution models. Models that only include the advection of angular momentum by
meridional circulation and shear instabilities cannot reproduce current
rotational constraints, irrespective of the initial conditions. The latest
formulation of internal magnetic fields based on the Tayler instability is
indeed able to reproduce the internal rotation rate of post-main sequence
stars, however, it appears too efficient during the main sequence and has thus
been disfavoured. A less efficient version of the same transport process can
simultaneously reproduce the rotation rate of the convective core, the rotation
rate in radiative regions as probed by gravity-modes, and the surface
rotational velocities of $\gamma$ Doradus stars. Our work suggests that there
are additional physical processes apart from internal magnetic fields at work
in the stellar interiors of post-main sequence stars.
