The influence of base fluids on the anti-shudder properties of transmission fluids for wet clutches in all-wheel drive systems was studied. The all-wheel drive system, featuring a wet multi-plate clutch with a sintered brass base friction material, was described. Five different fluids (Fluid C = semi-synthetic, Fluid A and E = synthetic based fluids combined with the additive package from Fluid C, Fluid B and D = mineral based fluids combined with the additive package from fluid C) were used. Fluids A and B were low viscosity fluids while Fluids D and E were high viscosity fluid. The low viscosity base fluids presented a higher temperature dependence of the dynamic friction, μ50, compared to high viscosity fluids. These low viscosity fluids had better anti-shudder properties compared to the high viscosity fluids, especially at lower temperatures. The friction characteristics were mainly additive dependant, since large differences in the friction parameters could be observed from tests run at temperatures corresponding to a given viscosity. Synthetic and mineral base fluids showed similar behavior while the semi-synthetic commercial fluid presented better performance in some areas, implying that the additive package lose some performance when placed in a different base fluid than the originally intended. This is an abstract of a paper presented at the Technische Akademie Esslingen 14th International Colloquium Tribology (Stuttgart/Ostfildern, Germany 1/13-15/2004).