On Some Transmissions, the Thrust Washer Union has a Ridge -A-

Fig 1: Identifying Thrust Washer Union And Differential Housing

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Also, the differential housing has a groove -B- all the way around it.

-- Insert thrust washer union with transmission fluid.

-- Install the thrust washer union so that it fits into the groove -B- in the differential housing.