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S4 T2 Diff Rebuild: Need Advice

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Old Oct 15, 2015 | 09:41 PM
  #1  
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S4 T2 Diff Rebuild: Need Advice

Hello Everyone,

I'm in the process of attempting to rebuild a pre-'87 T2 diff. This is my first time rebuilding one. So, I don't know what type of wear is still acceptable. Before I get started here is a quick background: I bought the diff over a year ago with intentions to rebuild it or replace it with an aftermarket diff. I've never driven on it, and she was rather rusty on the outside. Due to my financial situation, an aftermarket diff is out of the question and I will rebuild it for now (so please keep the "a kaaz is only $350-400 more, why not get that?" comments away lol).

Okay, so I drained the diff fluid and noticed a little more metal than I would normally expect. I found these pieces and wondered what could they be? The ring and pinion gear were fine.
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I then decided to remove the differential from the housing to inspect the internals.
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Upon inspection I found two disc welded together and one of them was missing the internal teeth. That's where the metal came from!?
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Below is the wear on the housing for the spider gear and the melted carnage on one of the gears. So, in your opinion is this still safe to use with a little grinding and time to smooth out the edges? Thankfully the damage is not so much on the contact area.
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And this was the inside of the diff. Some scratches on the inner surface. Not sure if it's a big deal since the clutches are not in contact with that surface.
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Old Oct 16, 2015 | 10:26 AM
  #2  
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From: https://www2.mazda.com/en/100th/
you might see if that side gear is still available, Mazda lists it as P090-27-251 up to a build date of 9/1/87, and then it goes to a P090-27-251B, not sure if there is a difference between early and late. you need to call a dealership, no online reseller will list this part
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Old Oct 16, 2015 | 08:05 PM
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Thank you j9fd3s. I'll include that with my list of replacement parts and price out how much all the parts will be. If it creeps close to a kaaz unit I may have to bite the bullet and get one. Thanks again!
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