Oil in the driveshaft tube

[JM 35 Sedan]

The tt seal in post #7 looks like it might run/seal at about center of coupler on the solid type driveshaft used in 38/39 to 48. It also looks like it could seal on the earlier tubular driveshafts but may require a slightly different seal inner diameter pressed into the seal mounting tube as shown in that picture. A very nice design but seems as though it would move the tt forward by the thickness of the flange and extra gasket. Maybe that's not an issue?