A conveyor and conveyor drive for filling a combine grain tank includes a chain and paddle conveyor in a housing (114) that feeds an intermediate chamber (116), a gearbox with a first coupling element (208), the first coupling element (208) having teeth (230) with holes therethrough to permit the expulsion of grain from between the first coupling element (208) and a second coupling element (210) that is connected to a pivoting auger conveyor (104).