1976-1983 240D 3.69
1976-1981 300D/CD= 3.46
1978-1980 300TD=3.46
1981-1984 300TD=3.07
1982-1984 300D/CD=3.07
1978-1984 300SD=3.07
1985 300D/CD/TD/SD=2.88

No W123 ever came with a ratio higher than 2.88