I see that there are two sizes for rear main seals here on Pelican Parts; Repair seal 93 X 114 X 14 and a Stock size 93 X 114 X 13. Any ideas about which I should use? I am replacing the old crank seal while I have my transmission out - the car is an 87 300D. I don't know if the current one leaks, but I'm just going to replace it while I have the transmission out.

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1987 300TD named Klause
1987 300TD named Spouse
1987 300D named Seabiscuit
1980 300TD names Chloie (now sadly gone)