After removing all drivetrain related equipment including engine on the '59 CJ5, I replaced the old rope rear main oil seal with the neoprene unit. I thought I followed all the instructions; including a dose of RTV sealant, torqued everything down and reinstalled. I still have a leak! I'll get under there soon and check torque on the oil pan bolts, etc. But in the end looks like I'll have to live with it.