  We calculate the current-pressure relation for pinholes connecting two
volumes of bulk superfluid 3He-B. The theory of multiple Andreev reflections,
adapted from superconducting weak links, leads to a nonlinear dependence of the
dc current on pressure bias. In arrays of pinholes one has to take into account
oscillations of the texture at the Josephson frequency. The associated
radiation of spin waves from the junction leads to an additional dissipative
current at small biases, in quantitative agreement with measurements.
