HO52 woes

[JMD]

Hey all,
I took my '68 k10 out for it's first test drive and found that the rear axle (Eaton HO52) is leaking from the pinion area. The yoke does have a bit of a groove in it from the pinion seal, so I had it sleeved and installed a new pinion seal thinking this would solve the problem...It did not. I also coated the splines with industrial thread sealant but it still drips a few drops every hour. However on my 2 mile test drive the entire back half of the truck became coated in gear oil, so the leak must get worse as it drives.

What else should I be looking at? Any ideas are appreciated, thanks.