BIGREDDNESS

I just had my rear-end start to leak a little, know it came from the pinion I went and got another seal and it is still leaking. My rear-end is a 10 bolt GU6 3.42. The problem(besides the leak) is that 1.) from what I have read here and on other sites is that the fluid should not be to the bottom of the fill hole, and it should be any where from 3/8in to 1 5/8 inch below the fill hole,,,so do i just wing it on the fluid level? it about 3/8 below because i cant touch it with my little finger....and #2.) there is a pinion seal on the front of the diff. and also another one on the yoke that seals to the flat of the pinion seal after you put the yoke back in. There in lies the problem, no body can tell me about this yoke/pinion seal or has even heard of it and the only way to get another one so far is to take it all apart and get the number off of it. So does anyone know this seal number by chance and know how much fluid to really put in????