We have studied the lattice location of the transition metals 61Co (1.6 h) and 65Ni (2.5 h) in Si single crystals of various doping types by means of on-line Emission Channeling using Short-Lived Isotopes (IS453 EC-SLI). 65Ni was directly obtained by means of Ni RILIS ionization, while for the 61Co experiments we implanted the short-lived precursor isotope 61Mn(4.6 s) which decays via 61Fe (6 min) to 61Co, during the Mn RILIS run. In this case only measurements after a waiting period of 30 min were considered. The samples were low-doped n-Si (7.3-12 Ohm cm, in the following named i-Si), as well as highly p+ (0.0053 Ohm cm) and n+ (0.0030 Ohm cm) doped Si. While full quantitative analysis of the measured EC-SLI patterns by means of fitting to the results of manybeam simulations of emitter atoms on various lattice sites has not yet been performed, a qualitative inspection gave the following preliminary results. Directly after room temperature implantation, the major lattice sites occupied by 61Co and 65Ni were substitutional or near-substitutional sites in all doping types studied. However, after annealing at 500°C 65Ni changed to tetrahedral interstitial (T) sites in i-Si and p+-Si, while the majority of 65Ni in n+-Si was found on bond-centered (BC) interstitial sites after the same annealing temperature. Site changes to interstitial T sites were also observed for 61Co in i-Si and p+-Si, while the case of 61Co in n+-Si is still waiting to be measured at next year's Mn beam time. The behaviour of Co and Ni in Si shows hence some similarities to Fe in i-Si, where site changes from near-S to T sites were already observed in previous experiments. However, there are also clear differences. While the site changes S->T in the case of Ni and Co occurred already after annealing at 475-500°C, in the case of Fe in i-Si around 600°C was required in order to promote the corresponding effect. Also, while Fe showed considerable resistance against high-temperature annealing, which went along with the occupation of ideal substitutional sites after 900°C annealing, Co and Ni started to show partial out-diffusion from the samples already for annealing temperatures in the 600-850°C range.