BMW new G2 & G3 Front & Rear Differential fluids question.

rav

Joined
May 20, 2011
Messages
44
Location
NC
I hope that some of you gear heads can maybe explain to me the REAL reason for BMW's Front & Rear Differential GL5 viscosity fluid change.

I own & maintain 5 current BMW's of different years & models (92 E34 535i, 01 E39 540i, 05 E46 330ic, 07 E83 X3 & newest 15 F15 X5.
It's time to drain & fill the X5's Front & Rear Differential fluids. When I go to the BMW Tech site & FCPEuro, they specify the following:
Front Differential with a G2 fluid, which is a GL5 75W85 @ $59.49/ .5 liter
Rear Differential with a G3 fluid, which is a GL5 70W80 @ $80.49/ .5 liter
Both take a little over .5 liter, so I would need to buy 2x .5 liters of each, which is $280 just in gear oil. It's even higher if you purchase from a Dealer.

My question is Why would they (BMW) change from the standard 75W90 GL5 oils? Is there that much difference in these newer fluids?

Why can't I just use a 75W85 GL5 fluid like Red Lines 75W85? It's a good grade GL5 & the same weights as the G2. And why drop the weight to 70W80 for the rear?

Do you think that they have done this to be more GREEN? That would be a better MPG from a lighter fluid OR less harmful chemicals to the environment?

I'm just looking for someone that might know or understand the REAL reason?

Your comments are appreciated.
 
I'd put the vehicle into the redline oil selector and use with confidence.. if there is an issue they wont list a product.

most likely the viscosity change is for MPG.. but BMW IIRC they switched to GL-4 in some who knows why they make some choices except that they can.
 
  • Like
Reactions: rav
I'd put the vehicle into the redline oil selector and use with confidence.. if there is an issue they wont list a product.

most likely the viscosity change is for MPG.. but BMW IIRC they switched to GL-4 in some who knows why they make some choices except that they can.
Thanks for the quick reply Rand.....And I agree with you as far as the "they can". I worked for a Germen Tool & Die shop for over 40 years, as a mold & die designer, Engineering Manager & VP of Sales Accounts. I designed & built tooling for Bosch, VDO, Siemens, Pierburg, Continental, BMW, etc, so have worked with their engineers & management. They have a mind set to obtain the most minute betterment on all their engineering & products. It's expected.
 
Far as I can tell from working of thousands of German cars is that they want to car to basically explode just after the warrantee expires. That certainly when the oil leaks start, and then it all just goes to hell from there on. Oil selection just a part of the planned obsolescence, and the obedient consumers do just what they are told.
 
  • Like
Reactions: rav
most revised lubes are all about mpgs, as noted check redlines web or call them!! as long as its the correct GL4 or GL5 lube you should be fine. GL5 usually NOT for yellow metals + i never trust backward compatible!!
 
  • Like
Reactions: rav
Far as I can tell from working of thousands of German cars is that they want to car to basically explode just after the warrantee expires. That certainly when the oil leaks start, and then it all just goes to hell from there on. Oil selection just a part of the planned obsolescence, and the obedient consumers do just what they are told.
Completely uninformed and nonsense post.
 
Far as I can tell from working of thousands of German cars is that they want to car to basically explode just after the warrantee expires. That certainly when the oil leaks start, and then it all just goes to hell from there on. Oil selection just a part of the planned obsolescence, and the obedient consumers do just what they are told.
As far as I can tell, you didn’t work on thousands of German cars. Now, thousands toys, maybe.
 
Been digging into a couple of things, and I am going to later post a correction in another current thread in which I recently posted about this...

I have an 2011 F10 X-Drive and I had a really interesting time going through differential lubes before a change a couple of years ago. There was differing info in different parts systems, and the local dealer parts manager and the parts/service liason had a lot of trouble figuring things out as well with what was published in parts systems for my VIN at the time.

My rear diff had a number of fluids specified, including SAF-XO and Synthetik OSP. Whenever you see SAF-XO that means pretty much any quality 75W90 GL5. The front diff had only G1 or G2 listed (G3 didn't exist). The thing that REALLY threw me for a loop was that G1 is GL4 (I incorrectly stated in a recent thread that G2 was GL4). At the time, I could find NO information on G2 except by buying a bottle at the dealer. I thought it said GL-4 on the bottle too, but current pictures online show G2 coming in a bottle marked GL5.

So, at the time, I made the cautious decision to go with G2 from the dealer for the front diff since there was a good chance that's what came in the car *AND*, particularly, the G1/2 series of fluids appeared to be GL-4. I had learned here many years ago that GL5 can damage some kinds of metals. I did not wish to throw a GL-5 into the front diff without knowing why the factory fluids appeared to be GL-4. At the same time, I observed Redline and Amsoil remove their recommendation for use in the front diff from their application guide.

With today's knowledge that G2 and G3 appear to be GL-5 and simply changing to get thinner, I would make a different decision. I would likely run Amsoil SVG or Redline 75W90, the SAF-XO spec.

Digging into the online parts systems today like RealOEM and bimmercat, I see them saying NOW that SAF-XO is on the list for my front diff. This was absolutely not the case ~2-3 years ago when I serviced my diffs. I am looking for phone pictures I took of the G2 bottle (I swear it said GL-4 too) and screen caps I may have saved in my car maintenance records from the parts systems. It's really bugging me how it looks like information changed. Though, I suppose, it changed for the better for those of us trying to choose fluids.

EDIT: found the pictures of the G2 bottle. At the time, it didn't say GL4 or GL5 - no markings at all. This contributed to not knowing what to do and playing it safe at the time. If it now clearly shows as a GL-5 fluid I would expect that alternatives would be completely OK.
 

Attachments

  • IMG_0465.JPG
    IMG_0465.JPG
    112.7 KB · Views: 153
  • IMG_0466.JPG
    IMG_0466.JPG
    185.4 KB · Views: 155
Last edited:
@Craig....Thanks for your reply. What I have found is that BMW changed the P/N front & rear differential fluid P/N's to a NEWER version. This took place somewhere around 2011 or so. Both Front & Rear are GL5 Hypoid fluids BUT they changed the make up to a "thinner" specification, i.e. 75W85 for the front & 70W80 in the rear. I will also assume, that they probably removed some environmentally harmful additives AND specified a thinner/lower viscosity fluid for EPA mileage. Those 2 items seem to be the big push for all automotive companies as the governments make higher standard requirements.
With that said, since I 1st posted this thread, I believe the RED Line 75W85 would be OK for both, at a significant cost reduction from the $280 for the BMW oil. I found the best price locally at O'Reilly's @ $19.99/quart.
1638891174901.jpg
If you go to Red Lines website & check it out, it's says it's suitable replacement for the BMW 511 & 512 gear oil. Red Line actually also says that their 75W90 is recommended BUT the current BMW P/N's 511 & 512 don't show up on the compatibility list. So, I'll probably just go with the 75W85.

One other option is the Liqui Moly 75W90 GL5 oil.

Hope this helps others....
 
@Craig....Thanks for your reply. What I have found is that BMW changed the P/N front & rear differential fluid P/N's to a NEWER version. This took place somewhere around 2011 or so.

There was a specification change in 07/2011. I can't say that I saw any hard parts change spec, but fluids and many other components have 07/2011 production as a cutover.

To be clear, when I mentioned what was and was not specified for my vehicle, I was shopping for my 3-4/2011 production vehicle IN 2017 or 2018 and found the confusing stuff I found. G1 is def a GL4. G2 at the time had no markings but now has GL5 markings. Now online parts systems list SAF-XO for the front diff, which they certainly did not years ago.

So - a bunch has changed :)
 
  • Like
Reactions: rav
I recently changed the rear differential Fluid in my All4 JCW Mini Countryman. Used the specified G3 which is a GL5 70w80. It is expensive, but, I wanted to keep the OEM fluid in this car. Only have 26,000 miles on it. No drain plug, aspirated 375 mL out, put 375 mL back in, used a new fill-plug since the O-ring seal is built into the plug.

I was going to change the GKN-developed electromagnetic clutch fluid back there (right in front of the differential), but, decided against it. There are reports that the unit's ECU may need to be reset if the fluid is changed due to the difference in viscosity, so, as clean as the differential fluid looked, I'll leave that alone. Maybe once I get a electronic device capable of resetting things like that, I'll change it then.
 
I was going to change the GKN-developed electromagnetic clutch fluid back there (right in front of the differential), but, decided against it. There are reports that the unit's ECU may need to be reset if the fluid is changed due to the difference in viscosity, so, as clean as the differential fluid looked, I'll leave that alone. Maybe once I get a electronic device capable of resetting things like that, I'll change it then.

I don't buy that. Do you have a reliable source for that?
.
 
I don't buy that. Do you have a reliable source for that?
.
I believe the last place I read this was on the FCP Euro site where they were comparing various all wheel drive systems. Reliable? I can't say...but, I've read similar recommendations on a couple of other sites. It's enough to prevent me from screwing around with it, since it's supposed to be "lifetime" fluid after all.

It was hard enough to get confirmation that the correct rear differential fluid was BMW G3, a GL5 70W80. Once I was convinced that was correct, I went to the Mini Dealership to be certain, because a plethora of other "experts" were recommending much different fluids for my 2019 JCW Countryman All4.
 
"Lifetime" is a marketing ploy. The maker of the units say different. BMW says Lifetime transmission fluid & ZF says 40-50k kilometers changes. Doesn't take a rocket scientist to see through that disinformation.
 
"Lifetime" is a marketing ploy. The maker of the units say different. BMW says Lifetime transmission fluid & ZF says 40-50k kilometers changes. Doesn't take a rocket scientist to see through that disinformation.
No doubt. That's why I drain/measured/refill ATF and suction/measure/refill rear Differential at 26,000 miles. Also in my searches, found out to NOT fill until it runs out the differential fill hole on my car...that would be too much. First car I've had like that, but, it's also the first I've had without a drain plug on the rear diff.
 
.
Surprised to hear BMW says 'lifetime' supposedly. After all it's a multi-plate
clutch sitting in thin oil and clutches do wear, causing debris. Just like a Haldex
clutch. This debris will cumulate in some kind of a filter (screen) and eventually
block it, impede the pump to flow oil and perhaps even to lock the clutch.
Believe me please, this system desires fresh oil every ~40k, much more than
your differential.
.
 
.
Surprised to hear BMW says 'lifetime' supposedly. After all it's a multi-plate
clutch sitting in thin oil and clutches do wear, causing debris. Just like a Haldex
clutch. This debris will cumulate in some kind of a filter (screen) and eventually
block it, impede the pump to flow oil and perhaps even to lock the clutch.
Believe me please, this system desires fresh oil every ~40k, much more than
your differential.
.
I don't disagree with pro-active approach to these fluid changes. I'm pointing out that sometimes it's not as simple as a differential change...which turned out to not be as simple as every other differential I've had. Required fluid specs have changed, getting the volume correct has changed, and with a dedicated ECU mounted on the GNK-Electromagnetic Clutch which is sensitive to the slightest changes in lubricity/viscosity, perhaps needed a "re-set", I'm not going to be in as much of a hurry to approach this one...I do not (yet) have a scanner that could do the re-setting procedure, should it not perform well after getting new fluid in there. It's no longer like the 2013 Mini drivetrain.
 
Required fluid specs have changed, getting the volume correct has changed, and with a dedicated ECU mounted on the GNK-Electromagnetic Clutch which is sensitive to the slightest changes in lubricity/viscosity, perhaps needed a "re-set", I'm not going to be in as much of a hurry to approach this one...I do not (yet) have a scanner that could do the re-setting procedure, should it not perform well after getting new fluid in there. It's no longer like the 2013 Mini drivetrain.

Viscosity changes all the time (with temperature), just like any oil does. See
this datasheet (that's what I use in my VAQ's Haldex unit):


It'll be triple digit cSt below freezing point and like 5 cSt when highly loaded
on a hot summer's day. I'm aware my knowledge has its limits, however I still
just can't imagine how that GKN clutch would be able to 'sense' viscosity . . .

I don't want to argue with you, I just want to broaden my comprehension.
.
 
Back
Top