I bought a 68 4 door Dart Slant that has the strangest options.
A trailer tow package of HD cooling, HD suspenion, 10 inch brakes,
and a 3.23 7 1/4. Along with heavy duty seat spring w foam.

So it said 14k on the speedo and had a receipt in the glove box for two new bias ply tires installed in 1993 at 12k. And they were still on the car and looked new!

Lucky for me I took the car straight to a lube shop and had all the fluids changed. Found out that the diff was very low and the pinion seal leaked badly.

After driving it about 2k, and adding oil to the diff once more, the oil leak stopped and the diff got much quieter. But it still growls strangly.

I want to pop the cover off, but not sure what to look for on the ring gear for signs of "just throw it away" because of low oil. Any comments ?

If a car sits for a long time where it's subject to temperature swings and humidity there can be condensation inside the axle housing (and gas tank and...). You probably have some pitting on the part of the ring gear that was not submerged in oil. I would pull the axle cover, clean everything as best you can and put the cover back on. Refill with something good like Lubrication Engineers 704 Monolec gear oil. Chances are you won't see much of anything looking at the ring and pinion, but you never know.

_________________
Joshua

Also look at the small "spider" and side gears, in the center of the carrier, the spider gears will pit & chip on the tooth surface, then break.

As for noise out of a 7 1/4, most of the time it is caused by the outer axle shaft bearings... those make a lower "rumbling" sound... not the higher pitched howl or whine that worn gears tend to make.
DD

Thank you and happy holidays to all of you. You are a great resource of knowledge.
I will pull the cover, clean and change the gear oil. Thank you Doc, I will also pull the axles and feel the bearings.
I noticed the other day, at a slow walking speed, a single crunch noise that occours with each rotation of the wheel. It might have a burnelled ( spelled it wrong)bearing from sitting so long.

Its funny how many more sounds I hear when idling or moving slowly while close to a wall of a building. That extra reflection of sound is great.

Thank you and safe Holiday to All !