Method for assembling a planetary gear unit in a precise position

The method for precise position assembling a planetary gear unit consisting of a planetary gear, a planet shaft, a bearing, two thrust washers and two guide washers, especially for use in a planetary transmission for an automatic transmission of a motor vehicle consists in that the planetary gear unit is inserted within mean position tolerance, aligned and braced in a tool which tool has two displaceable stamps and two jaws with indented rings which jaws surround the stamps forming a ring and can be displaced independently of the stamps. By closing the tool, the indented rings clamp the guide washers until a constant pressure is exerted against them. The stamps are pressed against the ends of the planet shaft until they are forged.