Jacked my car up to work on the suspension and noticed the bottom of the diff was wet. I get under there and looks like the cause of the leak is this black canister. It's on the drivers side right next to the rear diff. Any ideas what it is and where that broken hose is supposed to go?

 

Charcoal canister, hose is the vent. I'd say more likely diff or tripoidal joint issue.

 

Yep, looks like grease or gear oil. The carbon canister captures fuel vapors from the tank into the carbon, and it is self-purged by vacuum from the engine intake when driving. Not possible for it to make the mess you have there.

 

One side of the diff(pictured) has sprayed fresh fluid everywhere, while the other side just has a little caked up near the casing. Side seals shot?

 

How are your diff bushings? If they finnaly failed then it could be from that. They're oil filled. Clean it all off, drive around and check it again. It will make itself known.

 

Confirmed it's the seals after a drive. Thanks everyone for the help. I was ready to plug the charcoal canister into a non-existent pipe and call it a day.

 

It does kinda look more like an axle side seal but like cr-rex said , the differential bushings will blow oil too. Either way it seems I’ve been there....

Rear axle/differential side seal—-> https://www.rx7club.com/3rd-generati...-seals-517073/

Differential bushings——> https://www.rx7club.com/3rd-generati...hings-1128159/

 

If you're replacing the side seals, you may want to go ahead and replace the bushings while you're at it. Regardless of the miles, the rubber is 25+ years old