8 1/4 axle inspection.

I have a 72 dodge dart, LA360, comp 262., 727. I had a 3.21 sure grip installed this winter. It was a little noisy at first, a whine when light throttle at 35 to 45. It recently got worse. I had a local shop drive it and they thought it was ring and pinion. They quoted $1250 to rebuild.

My plan is to put together a 8.75. My problem is this will take a while and the driving season is short here. I want to pull the cover off the 8.25 and see what's going on inside. The question is what to look for? What would it take for me to rebuild myself? I can live with some noise but don't want it to fail.