Check that the Bevel Box hasn't been overfilled, that can cause seal leaks. It should only be up to the fill level hole above the drain, about 300ml. For info, the Bevel Box pinion nut is LH thread and the seal is a National Oil Seal 224205. Pinion bearing preload is 18-10 lbs in torque.
good to know, I'd ordered the seals , when arrived I will unmount the Bevel Box, replace the seal and check the oil level.
What I'm wondering - the whole drive train including the gearbox is mounted in rubber bearings - so it is moving while running. The BV is fixed to the frame and it seems to me that the propeller shaft is not variabel in length, isn't that a problem ?
From the photos you posted, it looks like your car may benefit from the Steering Comfort Kit as well, to reduce the bump steer, unless you have the matching low riding early Suplex shocks and springs.
I didn't notify any problem with the steering, may be I have the 'early suplex shocks' ? what is the problem in detail ?
Thanks
Thorsten