Rear Differential Oil Change

Chocolate

Harpy Eagle
V
2019 CX-5 AWD
Does anyone have a copy of the rear differential change procedure for the 2017+ CX-5?

I believe the "Mazda Long Life HYPOID Gear Oil SG1" is the correct oil, and 1 quart should be sufficient. Are there any other parts I need?

This is something that should be simple to do.

There is one online here

http://www.mcx5.org/differential_oil_replacement-962.html

but I am not sure if it refers to the 2013-2016.5 models. I believe the differentials are slightly different.

I did search.

Thanks.
 
V
2016 CX-5 GT AWD
I have a '16. The gear oil mentioned is correct. The toughest thing for me to do was loosening of the plugs. Couldn't use a socket, had to get a wrench over the plug heads. The draining was simple: Removed upper plug first, to make sure it would come out, then drain plug. Had to pump the oil up into the fill hole. It took a little more to fill than was drained out...underfilled at the factory, I suppose.
 

Chocolate

Harpy Eagle
V
2019 CX-5 AWD
I have a '16. The gear oil mentioned is correct. The toughest thing for me to do was loosening of the plugs. Couldn't use a socket, had to get a wrench over the plug heads. The draining was simple: Removed upper plug first, to make sure it would come out, then drain plug. Had to pump the oil up into the fill hole. It took a little more to fill than was drained out...underfilled at the factory, I suppose.
Do you happen to know the socket sizes?
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
Does anyone have a copy of the rear differential change procedure for the 2017+ CX-5?

I believe the "Mazda Long Life HYPOID Gear Oil SG1" is the correct oil, and 1 quart should be sufficient. Are there any other parts I need?

This is something that should be simple to do.

There is one online here

http://www.mcx5.org/differential_oil_replacement-962.html

but I am not sure if it refers to the 2013-2016.5 models. I believe the differentials are slightly different.

I did search.

Thanks.
If you want to do rear differential, might as well do the front transfer case at the same time with the same Mazda Long Life Hypoid Gear Oil SG1. You do need more than 1 quart of SG1 for both changes, although the specs say you need 0.48 (front) + 0.37 (rear) quarts for gen-2 CX-5. In reality the rear would need at least 0.75 quarts.

Measure the used gear oil and report back how much the real differential is under-filled from factory. (uhm)

Heres an excellent thread for all of your questions. Although its for gen-1 CX-5, but everything should be applicable to gen-2 CX-5 other than rear differential gear oil capacity from specs.

Rear Diff and Transfer Case Fluid Change: tools parts and links
 
V
2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
If you want to do rear differential, might as well do the front transfer case at the same time with the same Mazda Long Life Hypoid Gear Oil SG1. You do need more than 1 quart of SG1 for both changes, although the specs say you need 0.48 (front) + 0.37 (rear) quarts for gen-2 CX-5. In reality the rear would need at least 0.75 quarts.

Measure the used gear oil and report back how much the real differential is under-filled from factory. (uhm)

Here*s an excellent thread for all of your questions. Although it*s for gen-1 CX-5, but everything should be applicable to gen-2 CX-5 other than rear differential gear oil capacity from specs.

Rear Diff and Transfer Case Fluid Change: tools parts and links
~0.75 quarts for the rear + ~0.48 quarts for the front certainly equals more than one quart. Better buy two...
 

Chocolate

Harpy Eagle
V
2019 CX-5 AWD
Thanks for the input. I guess there's not enough space to use a socket.

The rear differential is so easy to reach, I was entertaining the idea of changing the factory fill early. I cleaned quite a bit of metallic sludge off the magnetic drain plug in my previous vehicle at 35k miles, and the oil was very dark, compared to the light amber 75W-90 I put in.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
Thanks for the input. I guess there's not enough space to use a socket.

The rear differential is so easy to reach, I was entertaining the idea of changing the factory fill early. I cleaned quite a bit of metallic sludge off the magnetic drain plug in my previous vehicle at 35k miles, and the oil was very dark, compared to the light amber 75W-90 I put in.
You can use 23mm and 24mm special shallow sockets with 3/8 torque wrench as CX5-SO stated in his excellent write-up (and Amazon links for shallow sockets) I posted previously although some pictures had been lost. Its for gen-1 CX-5 AWD but everything should be applicable to gen-2 CX-5. The best reason to check rear differential early is the factory fill is way less than its supposed to be as the refill procedure in Mazda Factory Service Manual states to fill the fresh gear lubricant SG1 to the filler hole (as usual) but that would take twice as much than specified 0.37 quart!
 
V
2016.5 CX-5 GT AWD titanium/black 2016 Miata Club ST MT white
Thanks for the input. I guess there's not enough space to use a socket.

The rear differential is so easy to reach, I was entertaining the idea of changing the factory fill early. I cleaned quite a bit of metallic sludge off the magnetic drain plug in my previous vehicle at 35k miles, and the oil was very dark, compared to the light amber 75W-90 I put in.
If you elect not to change the rear end lube then at least make sure that it's topped off. Many a CX-5 has come from the factory with considerably less oil in the rear diff than it will hold. I had to add 12oz to mine to bring it up to the level of the threads on the fill plug (which is where the shop manual states it should be when full).
 

Chocolate

Harpy Eagle
V
2019 CX-5 AWD
What would be the reason Mazda would not fill the rear diff to capacity at the factory, I wonder? Seems like they are all like this?
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
What would be the reason Mazda would not fill the rear diff to capacity at the factory, I wonder? Seems like they are all like this?
Not just rear differential, many have found the oil level on 2.5L and engine coolant are always below the Full mark from factory. Many have also verified the ATF is lower than specified range of dipstick from factory too. The reason? Money savings IMO.
 

erhayes

Contributor
V
Mazda CX-5 FWD Touring
I seem to remember many differentials only recommend to fill the unit to within 1/2 inch of the fill hole. Lubes do expand when used. Ed
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
I seem to remember many differentials only recommend to fill the unit to within 1/2 inch of the fill hole. Lubes do expand when used. Ed
I personally have only seen the gear lubricant level is to reach the brim of the fill hole in all similar applications (such as manual transmission). Its difficult to measure below the fill hole, might as well just design the fill hole below the current location and follow the convention of measuring method. If gear lubricant expands a lot like ATF, the manufacture would specify a temperature reference like filling the ATF.

Unfortunately several posted Mazda Factory Workshop Manual page pictures related to gear oil change procedures on front transfer case and real differential are all lost after our server update or Ill re-post here.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
Finally found a couple of pdf attachments thanks to our great Anchorman! I converted them to jpg's and here they are:

CX-5 AWD Transfer Oil Change.jpg

CX-5 AWD Diff Oil Replace.jpg


Just make sure when you follow the procedure, you need 0.75 ~ 0.85 quart gear lube for rear differential than stated 0.48 quart (0.37 quart for gen-2 CX-5).
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg. Plano, TX
Contributor
L
Plano, Texas, USA
V
16 CX-5 GT AWD Tec
bump,
if i cant get the sg1 i can use a 80W90 gl4 or 5?
tnx
You should be able to get Mazda Long Life Hypoid Gear Oil SG1 from any Mazda dealers or online stores including Amazon. IMO it’d be better off not to change these gear lubricants if you don’t use the SG1 for the change.
 

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