The dependence of magnetic and thermal transport properties on charge states of Mn and Co in LaMnO3 and LaCoO3, respectively, has motivated to perform a systematic study in the La0.95Sr0.05Co1-xMnxO3 (0.00 <= x <= 1.00). Substitution of Mn at Co-site leads to a decrease in both the thermopower (alpha) and the electrical conductivity (sigma) values. However, there is a concomitant increase in the magnetothermopower (MTP) values with an increase in Mn substitution close to paramagnetic to ferromagnetic transition temperature (T-C). We observe a tunability in the sign of magnetoresistance with an increase in Mn substitution. Thermal conductivity (kappa) exhibits a weak magnetic field dependence with magnetothermal conductivity (MTC) peaking close to T-C for 0.50 <= x <= 1.00. A maximum MTP is observed close to T-C in x = 0.95 sample. The dependence of a on magnetic field is found to increase with the enhancement of T-C in the system. We conclude that Mn substitution at Co-site not only improves the T-C in the system but also increases the effect of magnetic field on thermal transport properties.