I'm looking at some used differentials. Can any 300D from 1980-1985 be used on my car, or are there specific models that I'll want to avoid?

I just had the center support bearing replaced, and now I have a hum that only comes between 60-65 mph, then goes away. It's new.

There is another rotating vibration that is very low, I can feel it in the seat, that just gets faster with vehicle speed. It was present before the carrier bearing (which I hoped would fix it) but has gotten worse.

My CV boots are cracked, but don't appear to be leaking. They're on the list of things to fix soon.

Replacing the pinion bearing and seal, is this something that I can do on my own with jack stands in my garage or something that I'm better off paying a pro to do? I've done the engine mounts, valve adjustments, etc., so I'm not stranger to a wrench. But there are times when it really helps to have air tools and a lift.

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1982 300TD 300,??? miles, daily driver turned donor
1982 300TD, 184,000 miles, daily driver