Experimental studies were conducted on transportation of gas across radial shaft seals. Gas flow rates were determined with GC. Gas was pumped in, while gas also leaked at about half of the pump rate. Three polyalphaolefins (PAO-17, PAO-32, and PAO-63) and three paraffinic mineral oils (P-60, P-150, and P500) were used. The flow rates increased with shaft speed and oil viscosity, though paraffinic mineral oils allowed more gas to move than polyalphaolefin of the same viscosity. Gas was conveyed by hydrodynamic flow of oil at the seal lip. The rate was largest for CO2 and smallest for helium. This could be due to difference in dissolution of the gases in the oil. This is an abstract presented at the World Tribology Congress III (Washington, DC 9/12-16/2005).