Originally Posted by 75 racer
The seal is fairly easy to replace because you can unbolt tha axel and get it out of the way but with the growling noise I would be suspicious of the bearings in the diff. I would drain the oil and look for metal debris.
The fluid leaking out is clean, just changed it 6 months ago. If there are shavings, I'm looking at a rebuild? I used Mobil synthetic 85-135ish. I checked the boards, should have been fine. Maybe 80-90 is better.