To improve the effective interactions in the shell, it is important to measure the single-particle and single-hole states near the 28 shell gap. In this paper, the neutron spectroscopic factors of hole states from the unstable neutron-rich Ar ( 18, 27) nucleus have been studied using the H(Ar,) Ar transfer reaction in inverse kinematics. Comparison of our results with the particle states of Ar produced in H(Ar, ) Ar reaction shows that the two reactions populate states with different angular momenta. Using the angular distributions, we are able to confirm the spin assignments of four low-lying states of Ar. These are the ground state (), the first-excited state (), and the and states. While large basis shell-model predictions describe spectroscopic properties of the ground and states very well, they fail to describe the and hole states.