Got a rear years ago, was told it was an 8 3/4 from a 71 Charger and was told it would fit perfectly in my 71 sat.

Pictures are here. http://s2.photobucket.com/user/shirowfan/slideshow/Rear

Pictures are after it soaked in Trans fluid for a month.

Would it be safe to run with the pinion rust damage I can probably clean it up with some light 400 grit hand sanding.

Any info is appreciated. I'm out of my league with rear/trans stuff, have no idea what I'm looking at.

Not sure why you decided to make it a slideshow, it's irritating.

I would run it.

I see no issues that would prevent me from running it. Go for it.

Your presentation technique is fine by me. I ain't an expert on gears but I would think unless someone says it is totally shot (& I sure dont think that is the case here) that the only real option/way to find out is to install it. when the time comes post how it does.

It's hard to know if the pinion bearing is ok, but if it spins smoothly without making any nasty noises you should be fine.

The R+P gears cleaned a bit will be fine IMO.
I would be more concerned about the bearing condition, especially rust wise as well as the inner DIFFERENTIAL condition rust wise.
Two choices,
1. Roll the dice and run it
2. Rebuild it

Sorry about that. Is this better? http://s2.photobucket.com/user/shirowfan/Rear/story

I'm not too good with photo bucket since they stopped their third party hosting stuff. Is there a way to just direct people to a folder?

As far as the rear goes, I bought it a long time ago (whole thing) bolted it under the car but then it went through like 5 garage moves over the last 20 years. I'm guessing the rust is probably from sitting in one position for an extremely long time, and hopefully only affected that area.