UPDATE...Well a friend with a lift and a compressor helped me out today. I purchased the correct pinion seal from Dr. Diff. last month. Once we pulled the yoke we discovered a deep wear ring around it! This unit was "rebuilt" by Wade at Mancini's back in the mid 90's. It has only 1,200 miles MAX on it. I find it very difficult to believe they used a new yoke when it was rebuilt. Anyhow, We were able to remove the yoke from the 742 case 3:23's I had in my garage, and the yoke which had approx. 90,000 miles on it looked really nice. So...it was really the yoke which was causing the leak rather than the seal - we did replace the seal anyway.