Take a look at the facroty Diff Fluid @ 50,000

[Rawyzf]

Changed The Rear Differential Fluid - Look Inside

We just rolled over 50000 miles, so I figured it's time to change the Rear Diffenential Fluid. Next up will be the Transmission Fluid and Transfer Case (sometime over the next couple weeks).

We also replaced the Brake Rotors and Pads, as the rears would not stop squeeking. So I just replaced them all.

For replacement fluid, I used: Castrol Limited Slip 80W-90 (info below)

• Castrol Axle/Axle Limited Slip Gear Oils
  • Axle Limited Slip 80W-90
    • Recommended for service fill of all lmited slip differentials in passengar cars and light trucks calling for SAE 80W-90 and API Service GL-5 specifications
    • Recommended for applications calling for Ford ESP-M2C154-A, GM 9985290
    • Recommended for service fill of conventional adn limited slip differentials calling for API Service GL-5, SAE 80W-90 gear oil

Did any of you who have changed the fluid have the old fluid look like this? I don't recall ever seeing a silver metallic colored fluid.

 

[sts7049]

whoa. never seen fluid that color either.

 

[Bgallodoro24]

Could that be some type of grease they use to put parts together at factory?

 

[Rawyzf]

No idea, I'm going to email Mazda and ask.

 

[robertof]

I haven't change the diff oil in the CX-9 but when I did it on the speed6 at 80K miles it still looked good and nothing like your pic OP.