66 pinion leak around the nut

[jeff66tbird]

Refurbishing my 66 where necessary and had a leak around the pinion nut out onto the u-joint (see attached picture) without the appearance of a leak from the outside radius of the pinion seal completely down to the bottom of the differential that you may normally see from a pinion seal leak. When I went to loosen the pinion nut, it was not tight and came loose easily with the first turn of a socket wrench. I have marked the original position of the nut, yoke, etc. and was considering retightening the pinion bearing preload for a collapsible spacer with used bearings beyond the original position that I marked to an additional 10-14 in-lbs like the shop manual recommends without changing the seal. I have a WCD-J code tag on the differential for additional information. Also, I have a short video of play in the yoke with pinion nut in original position but can't seem to upload it. Not sure if it is too much play but appears to be a half inch. Obviously, not planning on running this car too hard. Thanks for whatever advice or opinions.

[Rt.146]

There is a seal for the pinion gear assembly, there is also a vent on top of the right rear axle if it gets plugged, it can blow that seal, the vent is easy to clean with a thin wire, though the damage may be done.

[Jimntempe]

Sounds like a reasonable plan to me. I would assume 1/2" play is the side gears, no way the pinon could have play like that. Is it possible the grease you see has come out of the ujoint?

[jeff66tbird]

I appreciate the responses. When I backed off the pinion nut slightly, I got a slight leak of gear oil with that distinctive smell so doesn't appear to be a small amount from a u-joint. Believe I will try tightening the pinion nut down to the additional torque of 10-14 for the used bearings without changing the seal since no leaks are appearing on the exterior circumference of the seal but around the center nut. My only concern is not tightening it too much on what I assume to be a crush sleeve on the pinion shaft.If others have further advice or thoughts, please share if you would like. Thanks.