Abstract: In a transmission housing for motor vehicles, which consists of magnesium or a magnesium alloy and is provided with reinforcement ribs having rounded base sections, transverse ribs which extend in the rounded base sections of the housing ribs and the transmission housing wall is relatively thin and provided on the outside at least partially with a waffle-patterned surface reinforcing the housing wall thereby saving weight and providing in the manufacturing process for good casting flow conditions and cooling properties.