Need recommendation on rear differential oil

Hello...new to the forum..

My 2008 CX-9 Touring AWD is due for rear differential oil change. The manual specifies "API Service GL-5 (SAE 80W-90)". Can you recommend any brand name that you have used in this model?

I have found Royal Purple 80W90 at Amazon:

Royal Purple 11687 HPM Gear Lube 80W90 High Performance Synthetic Marine Gear Lubricant - 1 Quart

https://www.amazon.com/dp/ (commissions earned)

Can this be used? Is the "Marine" supposed to be better?

Or, should I use 75W-90 rather than 80W-90? Does it matter?

Royal Purple 01300 Max Gear 75W-90 High Performance Synthetic Automotive Gear Oil - 1 Quart

https://www.amazon.com/dp/ (commissions earned)


Any other recommendations?

Appreciate any input..thanks!

Either would be fine. The marine will tolerate moisture intrusion a bit better, but i also like the slightly better cold flow of the 75w. I would just use Mobil1 75w-90 off the shelf at the local auto parts store for $10. Seeing as how our AWD systems are on-demand and not full time i wouldn't spend $18 on diff fluid.

And while you're changing out the rear diff fluid... have you done any research on the front diff fluid? I'd be more concerned about changing that out. Haven't found much mention of that around these parts though.

Thanks for your reply Veilside1! I will try the $10 one this time.
On the front diff, correct me if I am wrong but my understanding is that the front diff is built into the transmission unit and they share ATF. So if you change ATF, the front diff is taken care of... No? Anyone? User manual does not mention front diff at all. By the way, transfer case is seperated from transmission unit and its oil must be changed seperatly (manual calls for API Service GL-5 SAE 75W-140).

segio said:

Thanks for your reply Veilside1! I will try the $10 one this time.
On the front diff, correct me if I am wrong but my understanding is that the front diff is built into the transmission unit and they share ATF. So if you change ATF, the front diff is taken care of... No? Anyone? User manual does not mention front diff at all. By the way, transfer case is seperated from transmission unit and its oil must be changed seperatly (manual calls for API Service GL-5 SAE 75W-140).

Click to expand...

This is how I understand it as well. I just did the rear diff with 80w90 Castrol.