How often should I change the differential oil in a Mazda CX-30

[pbm]

I've never had an AWD vehicle in the family until my daughter purchased her new CX-30 AWD last year.
How often should I change the differential oil and is regular 75w90 GL5 gear oil sufficient or is Mazda's OE stuff special? Does it have a differential in both the front and rear? Thanks in advance for any info on this.

 

[ctechbob]

Probably going to depend on the setup of the unit. Is it a torque vectoring unit with clutches that require something special (Honda SHAWD is like this) or just a plain ol limited slip diff.

Either way, it is probably small and doesn't hold much oil. Me personally would run a 30,000 mile schedule.

--Edit--
From the looks of this it seems like it is a standard(ish) rear diff with an electronically controlled viscous unit in front of it to control F/R power balance. In that case a regular GL5 is probably going to be the pick, likely 75W-90.

Driving Diff CA02-27-100D | RealMazdaParts.com

Save Big On This OEM Mazda Driving Diff, Part #CA02-27-100D for

www.realmazdaparts.com

 

[mcdonnell]

I just changed my diff and transfer case on my 2018 Toyota highlander 19,000 miles with redline 75-85 and the old stuff came out scary silver and magnets full. And the fill plug on the transfer case was a nightmare. Anyone attempting will need a 6 point 24mm socket and prayer.

 

[wpod]

The most wear happens when the unit is new. Decide on how long you want to run the oil. How long do you keep your vehicles.

 

[Asterix]

First change after new 5-10k miles. After that, every 50k miles is probably good enough. The service manuals never seem to talk about the early first change.

You could do a 2nd change 10k miles later and if the fluid looks good, extend to 50k.

wpod has the most important question: How much do you care about a long life?

 

[drtyler]

For a 2022 CX-5 with all wheel drive, the Mazda book shows:

Mazda Long Life Hypoid Gear Oil SG1, 75W-85 GL-4

for both the transfer case and rear differential.

I would think the CX-30 would be similar, but verify.

 

[pbm]

Thanks guys....I'll probably use the Mazda fluid and change it at the next oil change which would be @ approx. 25K. I'd do it tomorrow but I don't often have access to the vehicle with her work schedule.
I always plan on running vehicles until 300K but it never seems to happen and especially now that I'm retired and not commuting. I'd bet most small AWD's by Mazda, Honda, Toyota etc...are neglected in this area so a first fluid change at 25K is probably better than most.

Additional replies and opinions are welcome.

 

[Deamos]

Thanks guys....I'll probably use the Mazda fluid and change it at the next oil change which would be @ approx. 25K. I'd do it tomorrow but I don't often have access to the vehicle with her work schedule.
I always plan on running vehicles until 300K but it never seems to happen and especially now that I'm retired and not commuting. I'd bet most small AWD's by Mazda, Honda, Toyota etc...are neglected in this area so a first fluid change at 25K is probably better than most.

Additional replies and opinions are welcome.

I'm going to do my first Transfer case and rear diff fluid changes at 30K (atf will be done first at 60K) and then every 30K after for my CX5. Makes it easy for me to remember when the interval is coming up.

The first changes will be sometime next spring/summer with the pace I'm adding miles right now.

 

[Luftmasse]

I just changed my diff and transfer case on my 2018 Toyota highlander 19,000 miles with redline 75-85 and the old stuff came out scary silver and magnets full. And the fill plug on the transfer case was a nightmare. Anyone attempting will need a 6 point 24mm socket and prayer.

The transfer case fluid came out golden right?

It is usually the differential that beats the fluid up.

 

[pbm]

I found 2 quarts of Royal Purple 75W90 Maxgear with 'synerlec' in my garage that I bought at AA on 'CLEARANCE' a few years ago. It says it's "an outstanding choice for transmissions and other gearbox applications requiring a GL5 or GL4 gear oil"..... I'll probably use it in the Transfer Case and Rear differential unless someone on here thinks it's not suitable?

 

[ripcord]

Sheesh! You can put one of those quarts of RP back where you found it. Apparently, both the transfer case and the differential only take about a third of a quart. The link I posted says to use Mazda Long Life Hypoid Gear Oil SG1 which seems to be a 75w85 gear oil.

https://www.mazdausa.com/static/manuals/2020/cx-30/contents/10020103.html

 

[mcdonnell]

The transfer case fluid came out golden right?

It is usually the differential that beats the fluid up.

no, both were very silvery magnets were covered,

 

[Luftmasse]

no, both were very silvery magnets were covered,

That is unusual for this particular model.

 

[Stanley Milgram]

I found 2 quarts of Royal Purple 75W90 Maxgear with 'synerlec' in my garage that I bought at AA on 'CLEARANCE' a few years ago. It says it's "an outstanding choice for transmissions and other gearbox applications requiring a GL5 or GL4 gear oil"..... I'll probably use it in the Transfer Case and Rear differential unless someone on here thinks it's not suitable?

This is absolutely a suitable gear oil for the transfer case and rear differential.
splitting hairs between 75w85 GL5 and 75w90 GL5, both will keep the hypoid happy while the fluids are within their service life. You are going above and beyond changing the fluids in the first place but I do agree and would do the same if I were planning on holding the vehicle a longtime.

What I wouldn't do is use something like a Redline 75w85 incase the oe mazda stuff has better or different additives to help it hold up longer to maintain that 85 weight while hot, you could be downgrading from the oe fill.

If you don't use this 75w90 now, when will you ever? You said there are no other AWDs in the stable. It's not much of a bargain if you never use it.

 

[danbfree]

What is strange is that the factory is "Hypoid" gear oil AND is GL-4, when normally Hypoid gear oil is almost always a GL-5... But here's the thing, GL-4 is normally meant for manual transmissions with "yellow" (brass type) softer metals as the additive package for GL-5 is considered corrosive for these softer metals... so not only is 75w-85, which the Mazda OEM stuff is, is a less common weight, sometimes seen with Jeep also apparently, but obviously is called a Hypoid gear oil but is also GL-4, which is one of a kind, from what I can tell. Not that the OEM stuff made by Idemitsu is likely poor quality, but would be nice to know what 3rd party gear oil is acceptable/maybe even better at a more reasonable price.

From what I've seen, there are only a few alternatives to the OEM that mention "Hypoid" and GL-4 compatibility, these 3 all specifically mention GL-4 and GL-5 certification. I believe this dual GL-4 and GL-5 compatibility is also known as "GL-4+", they meet both certifications by having half or less of the GL-5 potentially corrosive additives. These 3 include Valvoline SynPower SAE 75W-90 Full Synthetic Gear Oil , Liqui Moly 20012 SAE 75W-90 GL-4 Gear Oil and Royal Purple 01300 Max Gear 75W-90 mention both "Hypoid" and "GL-4" compatible. The extra 5 points on the non Winter side (75w-90 instead of 75w-85) would likely mean just a touch thicker for hot summer use, and that sounds good to me. Specifically, the Royal Purple is the only one of the 3 to also specifically mention it is non-corrosive to the softer gears typically covered under GL-4.

So after all this looking around and researching, I'd only go with the Mazda OEM or one of these 3 to feel safe/100% warranty compliant. For me personally, I'm going to go with the Royal Purple to do my AWD Turbo Mazda3 at 20k miles (then let it go at least 40k more, if not longer after that). Maybe a subjective thing, but it sounds better than OEM and specifically states is non corrosive to GL-4 gears, so that is the deciding factor for me.

 

[pbm]

Here's an update....I changed the rear differential using the RP 75w90 about 7K ago (25K on vehicle at the time of change) and all is well. The OE fluid came out looking very good with only a small amount of ferrous fuzz on the magnet side of the plug. I plan on doing the transfer case soon as my daughter is going on vacation and the I'll have access to her Mazda for a week.

 

[danbfree]

I too went with the Royal Purple Max Gear 75w-90 for the transfer case and rear diff in my '22 Mazda 3 AWD Turbo and holy cow, what a difference! After splitting hairs, it seems the RP is the only one that specifically mentions is safe for hypoid gears and is GL4 compatible, both of which are super important to meet if going away from OEM... Well, feel like the car lost 500lbs the way it takes off and coasts with FAR less rolling resistance. Only $14/qt and each box only take 0.37qy so I still have 1/4qt left and nothing to use it on, hehe.

 

[danbfree]

Here's an update....I changed the rear differential using the RP 75w90 about 7K ago (25K on vehicle at the time of change) and all is well. The OE fluid came out looking very good with only a small amount of ferrous fuzz on the magnet side of the plug. I plan on doing the transfer case soon as my daughter is going on vacation and the I'll have access to her Mazda for a week.

OMG, def do the transfer case ASAP, I did both my gear boxes at once and it feels like the car (Mazda 3 AWD Turbo) is 500lbs lighter with how much better it takes off and coasts with FAR less resistance!

 

[dogememe]

I too went with the Royal Purple Max Gear 75w-90 for the transfer case and rear diff in my '22 Mazda 3 AWD Turbo and holy cow, what a difference! After splitting hairs, it seems the RP is the only one that specifically mentions is safe for hypoid gears and is GL4 compatible, both of which are super important to meet if going away from OEM... Well, feel like the car lost 500lbs the way it takes off and coasts with FAR less rolling resistance. Only $14/qt and each box only take 0.37qy so I still have 1/4qt left and nothing to use it on, hehe.

I’m a Lucas hater personally but they too claim their 75w-90 is gl5, gl4, mt1, and perfect for hyoid. So RP isn’t the only one. What all those claims are worth I have no idea.

 

[danbfree]

I’m a Lucas hater personally but they too claim their 75w-90 is gl5, gl4, mt1, and perfect for hyoid. So RP isn’t the only one. What all those claims are worth I have no idea.

Actually the Lucas does not claim anything about GL4 or Hypoid safe, I checked their photos and the full product data sheet and it is GL5 specific and that can be harsh for GL4 Hypoid gears...