A multi-compartment, sweeper-type rear loading refuse packer, with a compaction unit pivotally connected to the body. In the loading position of the compaction unit, the collection sumps at the back of the body are situated for receiving a respective load of segregated refuse deposited over a rear loading ledge at the back of each sump. At least one divider wall extends between respective two adjacent sumps from the rear loading ledge to the ceilings of the respective two adjacent compartments at the compartment openings, thereby defining respective loading channels from the sumps to the compartments. Each divider wall has a back portion with a top edge extending forward along adjacent sumps and a front portion with a top edge that rises obliquely from the top edge of the back portion to the ceilings of the respective two adjacent compartments at the compartment openings. The pack blade covers the channels and is drivable toward and away from the ceiling on an obliquely linear path along the top edge of the front portion of the walls, between a bottom limit position and a top limit position. The pack blade remains a part of the compaction unit when the compaction unit is pivoted upwardly into the discharge position.