OK Im about to change my Tranny Fluid and Diff Fluid for the first time.

How many quarts do I need again?

I ordered 1 qt of Redline MT-90 GL4 and 1 qt Redline 75-90 GL5.

Is this enough?

 

No:

ITEM Unit (US qt)
Manual transmission oil 2.05 qt (1.95 L)
Rear differential oil GL-5 75W90 1.3 qt


from the manual.

 

I checked levelness of my car before starting the fluid change and it did take additional fluid from that 3rd bottle before it started overflowing.

Remember to take the top fill plug out first in case you cannot get the drain plug out.

 

Sorry, it's "remember to take the fill plug out first, because if it won't come out after you pull the drain plug then you're in serious trouble"

There are other reasons too, but that's the main one

 

^This pretty much goes for any fluid change, but especially transmission, auto and manual.

Basically, you want 2 bottles of each.

 

Thanks guys!

Im not sure about what Mazda factory use for gear oil when the RX8 was made...but I heard good reviews about the Redline Synthetic Gear and diff oil...

The service manual was actually updated tp 60k every gear oil change on the series 2 RX8...Im hoping the Redline Gear Oil will give me more life out of my tranny

 

The Ford Motorcraft XT-M5-QS is a much better trans fluid. If you choose the Redline just be sure to shift carefully until the drivetrain warms up.

 

I agree the Ford Motorcraft XT-M5-QS is likely better - I didn't notice any change from the 40K mile dealer/factory fill and MT-90 replacement.

When you say carefully, is that to prevent damage or xs wear?

 

In my experience MT90 when cold makes the synchros very notchy and easy to grind if you try to sfift too fast or carelessly. This can lead to long term synchro issies IMP.

 

that is good perspective - now that my RX-8 has gone through a LD trip and DGRR2017 with MT-90 fluid change, perhaps another fluid change to Ford Motorcraft XT-M5-QS is in order. You can never change fluids too often (wink)!

 

Yes you can, but I also know it's pointless to try and debate it