My wife's car reached 50k miles today. BMW says the rear diff fluid is lifetime. I went ahead and replaced the diff fluid w Mobil 1 syn 75w90. I did not see a drain plug so I pump the old fluid from the fill hole. One quart was all I could pump out. The old fluid looked like the new. Car drives the same. Probably should have left it in til 100k. Oh well, it cost me $11 and 30 minutes. Think I'll replace the diff fluid every 50k miles.
Replaced diff fluid BMW 328i
- Thread starter barkingspider
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Go 100k on this fill?
Hi,
barkingspider - Seriously consider what BMW recommends - it is very credible advice
barkingspider - Seriously consider what BMW recommends - it is very credible advice
I would say changing every 100k would be sufficient when its a lifetime fluid. Considering you just did it now just do it every 100k going forth.
I changed out the original diff oil on a 2008 528i at about 195k. The old oil still "looked" fine, but I doubt it was in good shape. I refilled with Amsoil Severe Gear 75w90.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
Originally Posted By: The Critic
I changed out the original diff oil on a 2008 528i at about 195k. The old oil still "looked" fine, but I doubt it was in good shape. I refilled with Amsoil Severe Gear 75w90.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
Why do you doubt that the oil was in bad shape?
I change the oil my old BMW with a clutch-type LSD. I never have in my newer Torsen LSDs and open diffs.
I've read that the motivation for the "lifetime" fluids was that BMW found that transmissions and differentials were more likely to fail soon after being serviced. This overwhelmed any potential benefit from fresh fluid.
A single data point is hardly statistically valid, but having both axle seals fail soon after a fluid change adds anecdotal support to BMW's recommendation.
I changed out the original diff oil on a 2008 528i at about 195k. The old oil still "looked" fine, but I doubt it was in good shape. I refilled with Amsoil Severe Gear 75w90.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
Why do you doubt that the oil was in bad shape?
I change the oil my old BMW with a clutch-type LSD. I never have in my newer Torsen LSDs and open diffs.
I've read that the motivation for the "lifetime" fluids was that BMW found that transmissions and differentials were more likely to fail soon after being serviced. This overwhelmed any potential benefit from fresh fluid.
A single data point is hardly statistically valid, but having both axle seals fail soon after a fluid change adds anecdotal support to BMW's recommendation.
Originally Posted By: djb
Originally Posted By: The Critic
I changed out the original diff oil on a 2008 528i at about 195k. The old oil still "looked" fine, but I doubt it was in good shape. I refilled with Amsoil Severe Gear 75w90.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
Why do you doubt that the oil was in bad shape?
I change the oil my old BMW with a clutch-type LSD. I never have in my newer Torsen LSDs and open diffs.
I've read that the motivation for the "lifetime" fluids was that BMW found that transmissions and differentials were more likely to fail soon after being serviced. This overwhelmed any potential benefit from fresh fluid.
A single data point is hardly statistically valid, but having both axle seals fail soon after a fluid change adds anecdotal support to BMW's recommendation.
Likely to fail soon after change because the new fluid cleans up crud exposing a dry cracked seal
or
likely to fail because people use incorrect spec fluid?
Big difference
Originally Posted By: The Critic
I changed out the original diff oil on a 2008 528i at about 195k. The old oil still "looked" fine, but I doubt it was in good shape. I refilled with Amsoil Severe Gear 75w90.
The car came back for some other work several months later. By that point, both of the axle seals decided to seep. Oops.
Why do you doubt that the oil was in bad shape?
I change the oil my old BMW with a clutch-type LSD. I never have in my newer Torsen LSDs and open diffs.
I've read that the motivation for the "lifetime" fluids was that BMW found that transmissions and differentials were more likely to fail soon after being serviced. This overwhelmed any potential benefit from fresh fluid.
A single data point is hardly statistically valid, but having both axle seals fail soon after a fluid change adds anecdotal support to BMW's recommendation.
Likely to fail soon after change because the new fluid cleans up crud exposing a dry cracked seal
or
likely to fail because people use incorrect spec fluid?
Big difference
Bmw also says lifetime for the tranny fluid. I think its DEX VI. Perhaps I'll wait til 100k miles before I replace the filter and fluid
JHZR2
Staff member
Originally Posted By: Doug Hillary
Hi,
barkingspider - Seriously consider what BMW recommends - it is very credible advice
Doug,
Doesn't BMW still change out the driveline fluids on M cars at 1200 miles?
I wouldn't think that the castrol XJ or whatever is in there is any different...
It's good to hear the OP's fluid was clean and clear, and no murkiness from moisture...
Hi,
barkingspider - Seriously consider what BMW recommends - it is very credible advice
Doug,
Doesn't BMW still change out the driveline fluids on M cars at 1200 miles?
I wouldn't think that the castrol XJ or whatever is in there is any different...
It's good to hear the OP's fluid was clean and clear, and no murkiness from moisture...
Hi,
JHZR2 - I can't answer your M car question
I think OEMs have enough hard data to confirm their servicing recommendations with great confidence. As far as manual transmissions and diff lubricants go, these components are very reliable today (compared to past decades) with very few failures and this can be traced back in part to better quality lubricants
IME synthetic drive line lubricants are certainly lifetime fill products in the correct application and not subject to contamination in use in any way (water etc.)
As I've mentioned here before the lifetime fill policy in my OTR heavy vehicles was not problematical in any way over many millions of kms.
I think BMWs close relationship with their preferred Lubricant suppliers has helped them enormously. They are regular collaborators in in-field testing via Third Party suppliers too - and the Nurburgring helps in confirming lubricant durability - but end user application still rules
JHZR2 - I can't answer your M car question
I think OEMs have enough hard data to confirm their servicing recommendations with great confidence. As far as manual transmissions and diff lubricants go, these components are very reliable today (compared to past decades) with very few failures and this can be traced back in part to better quality lubricants
IME synthetic drive line lubricants are certainly lifetime fill products in the correct application and not subject to contamination in use in any way (water etc.)
As I've mentioned here before the lifetime fill policy in my OTR heavy vehicles was not problematical in any way over many millions of kms.
I think BMWs close relationship with their preferred Lubricant suppliers has helped them enormously. They are regular collaborators in in-field testing via Third Party suppliers too - and the Nurburgring helps in confirming lubricant durability - but end user application still rules
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OEMs have test data. Too often that data doesnt even come close to a what a consumer can do in a daily commute.
UOA the diff fluid for info. Cant tell how good it is by the looks.
UOA the diff fluid for info. Cant tell how good it is by the looks.
According to Amsoil, the rear differential takes 75W-140, not 75W-90.
Is the rear differential limited slip?
Make sure you have the proper fluid, BMWs are picky on fluids.
BMW rear diffs do have a drain plug.
Is the rear differential limited slip?
Make sure you have the proper fluid, BMWs are picky on fluids.
BMW rear diffs do have a drain plug.
Originally Posted By: Doug Hillary
Hi,
JHZR2 - I can't answer your M car question
I think OEMs have enough hard data to confirm their servicing recommendations with great confidence. As far as manual transmissions and diff lubricants go, these components are very reliable today (compared to past decades) with very few failures and this can be traced back in part to better quality lubricants
IME synthetic drive line lubricants are certainly lifetime fill products in the correct application and not subject to contamination in use in any way (water etc.)
As I've mentioned here before the lifetime fill policy in my OTR heavy vehicles was not problematical in any way over many millions of kms.
I think BMWs close relationship with their preferred Lubricant suppliers has helped them enormously. They are regular collaborators in in-field testing via Third Party suppliers too - and the Nurburgring helps in confirming lubricant durability - but end user application still rules
My son's X3 2.5i is still running the original gear oil in both the front and rear differentials- and at 178k miles they are both dead silent. That said, I do drain and fill the ATF every 60k.
The 25% LSD in the Club Sport gets a drain and fill every 60k, per BMW's service schedule for that model.
Hi,
JHZR2 - I can't answer your M car question
I think OEMs have enough hard data to confirm their servicing recommendations with great confidence. As far as manual transmissions and diff lubricants go, these components are very reliable today (compared to past decades) with very few failures and this can be traced back in part to better quality lubricants
IME synthetic drive line lubricants are certainly lifetime fill products in the correct application and not subject to contamination in use in any way (water etc.)
As I've mentioned here before the lifetime fill policy in my OTR heavy vehicles was not problematical in any way over many millions of kms.
I think BMWs close relationship with their preferred Lubricant suppliers has helped them enormously. They are regular collaborators in in-field testing via Third Party suppliers too - and the Nurburgring helps in confirming lubricant durability - but end user application still rules
My son's X3 2.5i is still running the original gear oil in both the front and rear differentials- and at 178k miles they are both dead silent. That said, I do drain and fill the ATF every 60k.
The 25% LSD in the Club Sport gets a drain and fill every 60k, per BMW's service schedule for that model.
Originally Posted By: stchman
According to Amsoil, the rear differential takes 75W-140, not 75W-90.
Is the rear differential limited slip?
Make sure you have the proper fluid, BMWs are picky on fluids.
BMW rear diffs do have a drain plug.
LSD ones take 75W140, that particular one was not LSD.
According to Amsoil, the rear differential takes 75W-140, not 75W-90.
Is the rear differential limited slip?
Make sure you have the proper fluid, BMWs are picky on fluids.
BMW rear diffs do have a drain plug.
LSD ones take 75W140, that particular one was not LSD.
Originally Posted By: dlundblad
100k for the ATF seems like a decent universal average.
Lifetime fluids only have to last as long as the warranty. I find it hard to listen to the manufacturer in this situation..
Mercedes-Benz has an interesting take on the lifetime ATF fill. I believe they recommend one change at 50k and it's lifetime fill after that.
I think the logic is that the one change removes fluid contamination from transmission break-in. After that the fluid will last a lot longer.
Modern ATF have excellent shear resistance and the viscosity is not supposed to change due to the quality base oil. The problem is the slow wear material accumulation.
If Mercedes-Benz is right, even if you change the ATF only ONCE, you're going to be in good shape.
100k for the ATF seems like a decent universal average.
Lifetime fluids only have to last as long as the warranty. I find it hard to listen to the manufacturer in this situation..
Mercedes-Benz has an interesting take on the lifetime ATF fill. I believe they recommend one change at 50k and it's lifetime fill after that.
I think the logic is that the one change removes fluid contamination from transmission break-in. After that the fluid will last a lot longer.
Modern ATF have excellent shear resistance and the viscosity is not supposed to change due to the quality base oil. The problem is the slow wear material accumulation.
If Mercedes-Benz is right, even if you change the ATF only ONCE, you're going to be in good shape.
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BMW open differential failures are about as common as unicorns. In 15 yrs on the forums I can't think of hearing about any.
It ain't 2000 folks.
It ain't 2000 folks.
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