  The Einstein's field equations of Friedmann-Robertson-Walker universes filled
with a dissipative fluid described by both the {\em truncated} and {\em
non-truncated} causal transport equations are analyzed using techniques from
dynamical systems theory. The equations of state, as well as the phase space,
are different from those used in the recent literature. In the de Sitter
expansion both the hydrodynamic approximation and the non-thermalizing
condition can be fulfilled simultaneously. For $\Lambda=0$ these expansions
turn out to be stable provided a certain parameter of the fluid is lower than
1/2. The more general case $\Lambda>0$ is studied in detail as well.
