Yoke seal

Two seals were used between 1965 and 1976 on 904 transmissions.
Timken 8935s from 65 to 72
Timken 2506 from 72 to 76
1972 could have either one depending on the PK number.
Since transmission could have been changed over the years, it would help to have the PK number stamped on the pan rail.