When I put the back cover on my diff I used a light coating of permatex copper (orange stuff). This worked well for me, I switch to the copper and seems to work very well.

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-Randy Wakefield

1969 220D 4 speed (parts car)
1976 280C
1976 280S
1981 240D 4 speed (parts car)
1982 300D
1983 300TD (Ivory)
1983 300TD (gold)
1985 300TD (gray)
1987 190D 2.5
1970 280SEL (sold)
1977 240D 4 speed (sold)
1974 280 (rusted to death)
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1927 Chevy 4 door sedan
1938 Chevy 2 door sedan
1950 Willys Jeepster
1955 Studebaker President 4 door
1977 Ford F250
1979 Glastron 17'
1948 John Deere A
1960 John Deere 2010
1979 Satoh S650G
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2000 Bichon (Doby)