Check the Rubber stuff:
Oil Cooler Hoses
Transmission Cooler Hoses
Drive Shaft Flex Discs
Drive Shaft Bearing Support
Rear Axle Boots (they are filled with Oil at the Factory cracks can lead to lubricant loss)
Motor Mounts (on the W123s when the left side Motor Mount gets squashed the Power Steering Belt has been known to cut through tha Oil Cooler Hose)
Oil Cooler Hoses
Transmission Cooler Hoses
Drive Shaft Flex Discs
Drive Shaft Bearing Support
Rear Axle Boots (they are filled with Oil at the Factory cracks can lead to lubricant loss)
Motor Mounts (on the W123s when the left side Motor Mount gets squashed the Power Steering Belt has been known to cut through tha Oil Cooler Hose)