Enables galactosylceramide sulfotransferase activity. Involved in galactosylceramide metabolic process. Acts upstream of or within galactosylceramide biosynthetic process; myelination; and spermatogenesis. Predicted to be integral component of membrane. Is expressed in brain; future spinal cord; heart ventricle; and spinal cord cervical region. Orthologous to human GAL3ST1 (galactose-3-O-sulfotransferase 1). [provided by Alliance of Genome Resources, Apr 2022]