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Total KM is 50000 on my C7 manual gear.
Today I changed the fluid and this is how it looked like, see picture 1.
Looks like previous owners have not changed it ever...!
Replaced it with Dexron, see picture 2.
When I changed lubricants in my first '19 Z, it was new and the diff fluid looked good. After losing that car to a careless driver last year, I replaced it with another similarly configured '19 Z with ~9K miles on it. When I changed its lubricants, the fluid diff fluid looked like yours.
Last edited by NortonCO; Oct 14, 2025 at 05:01 PM.
As mentioned, not bad. My 150k mile Rav 4 just got changed and it looked brand new. I put every mile on it, so I know it was original. I was surprised.
To be honest, if your rear diff fluid DOESN'T come out black I'd be surprised. It seems like that's pretty normal for the factory fill. I assume there are things in there its absorbing from the manufacturing process and that discolors it pretty fast (new metal parts are almost always coated to keep them from having any sort of surface corrosion).
Total KM is 50000 on my C7 manual gear.
Today I changed the fluid and this is how it looked like, see picture 1.
Looks like previous owners have not changed it ever...!
Replaced it with Dexron, see picture 2.
Originally Posted by TheGreenLanternC7
Yes I did both, thanks.
This I used for the trans, see picture
Since when do you use gear oil for both the tranny and diff. I never heard of that.
To be honest, if your rear diff fluid DOESN'T come out black I'd be surprised. It seems like that's pretty normal for the factory fill. I assume there are things in there its absorbing from the manufacturing process and that discolors it pretty fast (new metal parts are almost always coated to keep them from having any sort of surface corrosion).
Yes mine looked like that and was low at 8 years and 35000 miles. Told there was word they may have been underfilled from the factory...
Corvette has used ATF in the transmission since 1997 (first year of the C5) with the original Tremec T56. That continued with the TR6060 in the C6 (2005-2013) and the TR6070 in the C7 (2014-2019). All years, all models.
Many use the factory fill, I use Red Line D4 ATF (in my 2013 and 2019), others use Amsoil, etc. Regardless.....it's a flavor of ATF that's used and not 75W90.
Black Differential Fluid
proving, once again, how unintelligent AI can be.
