2013~2016 Question on CX-5 Rear Diff fluid change

[yrwei52]

Yup. My 2.5t takes a perfect 5.5 w/filter if I go by the stick.

And thanks for posting the info. With that info I would go to the hole and disregard the .48 qt instructions. But there is clearly an error on the diff data. Either .48 is correct or the fill hole is correct. Another poster says the fill hole is above the axle seal which is similar to the Chevy situation. I wonder if there has been a revision to the manual. Leaving the factory now to the fill hole would make me think yes.

Yes, either 0.48 quart or 0.7 quart for rear differential. Since you mentioned the leak issue on Chevy, and the factory fill is low too, I believe Mazda originally intended to use 0.7 quart for rear differential, then reduced to 0.48 / 0.37 quart due to the possible leak issue, although we haven’t seen any leak reports here (yet?) after people filled with 0.7 quart.

 

[ctbale]

I agree with you about people like me (when I was a young lad) who serviced a heck of a lot of "gear cases" will just pump it till it drools. So when I realized I over serviced my own truck after re doing the diff and seals ..... well my first thought was, thank you very little Chevy!

 

[ctbale]

Yes, either 0.48 quart or 0.7 quart for rear differential. Since you mentioned the leak issue on Chevy, and the factory fill is low too, I believe Mazda originally intended to use 0.7 quart for rear differential, then reduced to 0.48 / 0.37 quart due to the possible leak issue, although we haven’t seen any leak reports here (yet?) after people filled with 0.7 quart.

That's good to hear. 16oz is a pathetic amount of oil for a diff.

 

[yrwei52]

Hmmm. The more I scratch my head on this, the .48 might be correct. Gunna have to go take a peak at my diff and see what's going on with the casting below the Mazda diff fill hole. Like you said, if they wanted .48, lower the dam hole.

My take on this is I’ll fill the rear differential to the brim of the fill hole with 0.7 quart. With the AWD clutch pack in there, I’d prefer maximum amount of gear lube in the rear differential for better cooling. If it leaks at any seal, and nobody has reported this problem yet and chances are very slim, then I reduced the amount. The only thing is by doing 0.7 quart, I need 2 bottles of SG1 instead of one, that’s pretty expensive nowadays at $35.27 MSRP per quart!

 

[ctbale]

My take on this is I’ll fill the rear differential to the brim of the fill hole with 0.7 quart. With the AWD clutch pack in there, I’d prefer maximum amount of gear lube in the rear differential for better cooling. If it leaks at any seal, and nobody has reported this problem yet and chances are very slim, then I reduced the amount. The only thing is by doing 0.7 quart, I need 2 bottles of SG1 instead of one, that’s pretty expensive nowadays at $35.27 MSRP per quart!

Good points. I love messing with my car. I might just do the SG1 every 25k. Can't hurt, then just have to buy 1 qt. At 15k now so I better figure it out huh!? At 14k I pulled my brakes off and greased the caliper pins and did some minor cleaning here and there. I don't mind.

 

[yrwei52]

Good points. I love messing with my car. I might just do the SG1 every 25k. Can't hurt, then just have to buy 1 qt. At 15k now so I better figure it out huh!? At 14k I pulled my brakes off and greased the caliper pins and did some minor cleaning here and there. I don't mind.

Just noticed you have a 2022 CX-9 Touring, not a CX-5. I believe the capacities on front transfer case and rear differential should be the same as the CX-5 though. Please report back whatever you find interesting on this gear lube change.

 

[weitau]

You definitely want to change the gear lube in both front transfer case and rear differential at 158K miles.

CX-5 Rear Diff and Transfer Case Fluid Change: Tools, Parts and Links

A couple of notes: you need about 0.7 quarts of gear lube for real differential instead of 0.48 quarts stated in the manual. You need 0.48 quart gear lube in front transfer case as stated in the manual. Secondly, the factory fill in rear differential is pretty low as reported by many here.

The debate to me is what type of gear lube should I use on the 2014 CX-5? Mazda has changed the gear oil spec to Mazda Long Life Hypoid Gear Oil SG1 from traditional 80W-90 GL-5 since 2016 MY. SG1 is pretty expensive and you need to get 2 bottles for the change on both.

Thanks yrwei52, you're a walking encyclopedia! How you keep all these figures at your fingertips is amazing Since I have a 2014 with 158k miles, I suppose if 80W-90 GL-5 was good then, it should be better than anything in the diff right now. SG-1 is expensive. I have some Redline gear oil left over from a diff oil change from 15 years ago, maybe it's still good and the same viscosity. Otherwise Sae OEM 80W 90 R Diff Oil - Mazda PN# 0000-77-80W9-QT is pretty cheap at $11 online.

 

[yrwei52]

Thanks yrwei52, you're a walking encyclopedia! How you keep all these figures at your fingertips is amazing Since I have a 2014 with 158k miles, I suppose if 80W-90 GL-5 was good then, it should be better than anything in the diff right now. SG-1 is expensive. I have some Redline gear oil left over from a diff oil change from 15 years ago, maybe it's still good and the same viscosity. Otherwise Sae OEM 80W 90 R Diff Oil - Mazda PN# 0000-77-80W9-QT is pretty cheap at $11 online.

Yeh $35.27 per quart on SG-1 is outrageous! And you need to get 2 bottles for the change! The 2014 CX-5 manual says use any 80W-90 GL-5 gear oil for rear differential and front transfer case. As long as you have enough (1.2 quarts total) Redline 80W-90 GL-5 (make sure to verify it’s a GL-5) gear oil I’d think you can use it as I don’t believe the fresh gear oil has expiration date on it. Or any good name brand (Castrol?) or OEM gear oil which meets the specs should be perfectly fine.

I personally may consider to use SG-1 if I had a 2014. But that’s just me.

 

[weitau]

Yeh $35.27 per quart on SG-1 is outrageous! And you need to get 2 bottles for the change! The 2014 CX-5 manual says used any 80W-90 GL-5 gear oil for rear differential and front transfer case. As long as you have enough (1.2 quarts total) Redline 80W-90 GL-5 (make sure to verify it’s a GL-5) gear oil I’d think you can use it as I don’t believe the fresh gear oil has expiration date on it. Or any good name brand (Castrol?) or OEM gear oil which meets the specs should be perfectly fine.

I personally may consider to use SG-1 if I had a 2014. But that’s just me.

Yes, it's like choosing between synthetic vs dino engine oil. Hmm, I wonder if the SG-1 oil is synthetic? If it's more slippery, then the incremental fuel savings might be worth it. On the other hand, then there's the issue of mixing SG-1 with older gear oil.

 

[yrwei52]

Yes, it's like choosing between synthetic vs dino engine oil. Hmm, I wonder if the SG-1 oil is synthetic? If it's more slippery, then the incremental fuel savings might be worth it. On the other hand, then there's the issue of mixing SG-1 with older gear oil.

IMO Mazda switched the gear oil to proprietary SG-1 is to satisfy some functions the regular gear oil can’t offer to its rear differential. The capacity is very minimum (0.48 / 0.37 quart on spec or 0.7 quart in reality on rear differential), and the clutch pack in rear differential requires good heat dissipation when the slippage happens. There were several TSBs in early days on rear differential with premature wear on input shaft bearing that could have something to do with the switch.

Like engine oil, it shouldn’t be a problem at front transfer case and real differential of mixing different types of gear oil. The drain hole located at the bottom of the unit so that most old gear oil can be drain out.

 

[weitau]

Good to know!