Final Drive Viscosity?

feds27 said:

You jumped in mid conversation. Read a few posts back. When I posted about 80W140 I also mentioned my dealer used 10W50. I was just confirming for the skeptics that 10W50 was in my rider manual.

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No, I didn't jump in mid conversation. When you said "oil table" immediately after discussing final drive viscosity in the same sentence, you meant ENGINE oil table! Sorry I missed your intent (or was unable to read your mind).

BTW, your engine oil viscosity table must look very different from the ones for my three BMW bikes. Mine do not not use specifications such as "15W >= 40", they just have a table with all the approved grades (e.g., 20w-50) and the temperature range for each. Must be something new for hexheads.

BeemerMike said:

No, I didn't jump in mid conversation. When you said "oil table" immediately after discussing final drive viscosity in the same sentence, you meant ENGINE oil table! Sorry I missed your intent (or was unable to read your mind).

BTW, your engine oil viscosity table must look very different from the ones for my three BMW bikes. Mine do not not use specifications such as "15W >= 40", they just have a table with all the approved grades (e.g., 20w-50) and the temperature range for each. Must be something new for hexheads.

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The new '08 GS book has 20W50 listed as the engine oil, but then has a bunch of hieroglyphics about permissible grades versus temperature.
As far as the gear oil, I cannot find any reference in the owner's book on type and viscosity. It may be in there somewhere, but if so, they really dropped the ball on making it available...table of contents...index...no joy.
The repair data does however list the SAF-XO Castrol as the desired gear oil without mentioning the viscosity. Then go to the Internet and find out that Castrol states that it is synthetic oil and suitable when needing 75W90, 80W90, or 90. And that BMW recommends changing it (cars here) in the rear axle every two years.

soffiler said:

I have a good friend with an '07 GS-Adv. I have asked him to check. Will report back.

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The '07 GS-Adv Rider's Manual states both 15W / X and 20W / X are good down to 0C (32F). This is a definite change over the '05 GS Rider's Manual which allows 20W / 50 down to -10C (+14F).

cjack said:

The repair data does however list the SAF-XO Castrol as the desired gear oil without mentioning the viscosity. Then go to the Internet and find out that Castrol states that it is synthetic oil and suitable when needing 75W90, 80W90, or 90. And that BMW recommends changing it (cars here) in the rear axle every two years.

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Interesting. Although Castrol's product information indicates that BMW recommends changing the "rear axle" (differential?) oil every two years, BMW's stated maintenance requirements for their U.S. cars is that the manual transmissions and the rear differentials have "lifetime fills" and do not require changing the gear oil. The new cars do not have engine oil dipsticks any more. You rely on the engine oil level sensor to monitor your oil level (does that give anyone pause?). And I think the differentials no longer have drain plugs (if you want to change the gear oil you have to suck it out through the fill hole). I'll think I'll be keeping my 2001 Z3 3.0i for awhile.

Of course, no one really believes the "lifetime fill" BS (at least those who plan to keep their cars longer than the 4-year "free maintenance" period). I wonder what the European maintenance requirements are for transmission/differential oil changes?

BeemerMike said:

The new cars do not have engine oil dipsticks any more. You rely on the engine oil level sensor to monitor your oil level (does that give anyone pause?).

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I have an '06 325i. I bought it about 3 months ago, used with 21k miles. I always check the oil of any used car I even test drive. Freaked out is closer than taking pause. I hope the oil level sensor is made of unobtianium.

I'm changing the final drive lube in my '06 gs every 12k miles, whether it needs it or not.

Thanks for the tip on the rear differential on my car.

feds27 said:

The invoice doesn't state anything specific for the part numbers other than "10W50B" and "SYN1/2 QT 80W140B". The descriptions are "BMW 10W50 Motor Oil" and "1/2 QT 80W140". This service was performed by the dealer where I purchased the bike.

I spoke with the shop foreman about the 10W50 and he said they have NEVER seen an engine failure due to engine oil grade. Oils are much better than they were 20 years ago. The 10W50 oil will allow me to use the same oil all year round without the need to switch to 10W40 in the winter. I tend to agree with him.

I had asked about using 75W140 vs. 75W90 when I dropped off the bike. They said they haven't notice a correlation between fluid grade and failures. They only use the synthetic in the final drives and transmissions which they service. They said the 75W140/final drive issue is mostly internet hype. It could be those with failures had bad seals, bad FD's, or didn't perform 600 mile service where the FD fluid gets changed.

Anyway, I just wanted to share the info on these two other grades that are being used by the dealers.

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Ask your dealer to show you where -- in writing -- BMW recommends 75W140 for a hexhead final drive. I think you'll find they can't do that because BMW specifies Castrol SAF-XO, which is a synthetic 75W90 GL-5 gear oil. Since this product is not available at BMW bike dealers in the US, BMW USA sells a BMW-branded 75W90 synthetic. You'll find the SAF-XO specified in the repair manual and the parts fiche. I'd ask your dealer why they don't stock and use the lubricant BMW specifies. How much trust do you put in a dealer who can't even supply the lubricant recommended by the manufacturer? Who do you trust more on this issue, the company that built your bike, or the local yokel at your dealer? I love the dealer's logic (such a s it is) about failures and fluids. Now that makes me laugh.

You're going to love this...

I almost didn't buy another BMW this time around because of the issue of final drive faiure. Many I know in this community have a similar opinion. In the 70's I wanted a BMW motorcycle but couldn't afford one. Now I have my third and I want to do things right from the beginning.

I've spent the last several hours trying to learn more about this lubrication issue. Over the years I've read everything Paul Glaves and others have written about the FD issues in ON. I've discussed the problem with a very good local independent BMW shop, and poured over old reciepts to see what dealers had done with earlier bikes.

Now I have a new '09 Adventure, it's the newest bike I've ever had, and I want to do everything right from day one, so to speak. I've been a fan of Mobil 1 products in the past, but in talking with the service manager at my local dealership I was told to use a 75W-90 GL-5 synthetic lube in the final drive, but it needed to be suitable for NON-LIMITED SLIP rear ends. The newer Mobil 1 Gear Lube bottles are labeled LS. There are lots of 75W-90 GL-5 synthetic gear lubes out there, but finding one suitable for non-limit slip applications is a little tougher.

And while I believe my local service manager to be on the ball, it seems from reading this forum that many dealerships around the country don't know what they're talking about with respect to this issue.

So I finally decided to call BMW NA at 800-831-1117 and ask them. They MUST know, right? Well, the guy I talked to suggested I could also use 75W-140 in a synthetic lube and even 80W-90 in a non-synthetic! He didn't have anything in his database regarding a non-limited slip lube. So here we go again!

I suppose what I'll do for now, at least as long as I have a warranty (and I've heard BMW now will honor claims for the final drives for five years intead of three, I don't know any mileage figures, can anybody confirm that?) is use the BMW 75W-90 Synthetic Gear Lube (Spectro) at $23.25 qt. (ouch!) I already changed it at 600 and 3,000 miles, and I'll probably change it every 6,000 as well. That and check the temp. of the FD with my hand every four or five tankfulls. It will start getting hot to the touch long before it leaves me stranded along the road somewhere.

It would be nice if we could get a clear answer from BMW. It would be nicer if they would acknowlege the problems they've had with their final drives, issue a recall and get the bad ones replaced, and get confidence in their products back. The people that are reading this forum are the people that are trying to do the right thing by properly maintaining their bikes. My local service manager implied these final drive issues were caused by people that were letting their FD's go dry by leaking through the outer seal and said he'd never even seen an actual final drive failure. Hmmm.

marcopolo said:

Ask your dealer to show you where -- in writing -- BMW recommends 75W140 for a hexhead final drive. I think you'll find they can't do that because BMW specifies Castrol SAF-XO, which is a synthetic 75W90 GL-5 gear oil. Since this product is not available at BMW bike dealers in the US, BMW USA sells a BMW-branded 75W90 synthetic. You'll find the SAF-XO specified in the repair manual and the parts fiche. I'd ask your dealer why they don't stock and use the lubricant BMW specifies. How much trust do you put in a dealer who can't even supply the lubricant recommended by the manufacturer? Who do you trust more on this issue, the company that built your bike, or the local yokel at your dealer? I love the dealer's logic (such a s it is) about failures and fluids. Now that makes me laugh.

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My dealer has tried to get the SAF-XO and was told that you can't get it in this country...and another time that you had to buy a drum of it. So they stock the Spectro, BMW branded, long drain synth 75W90. And also stock the Amsoil synth 75W90 which costs about $12/qt or so. I would think that Mobil LS synth 75W90 is just fine for the bevel as well. I don't see how the small amount of friction modifier in it would affect anything.
BTW, the proper fill quantity now has been changed to 200ml from dry or 180ml on a refill.

cjack said:

My dealer has tried to get the SAF-XO and was told that you can't get it in this country...and another time that you had to buy a drum of it. So they stock the Spectro, BMW branded, long drain synth 75W90. And also stock the Amsoil synth 75W90 which costs about $12/qt or so. I would think that Mobil LS synth 75W90 is just fine for the bevel as well. I don't see how the small amount of friction modifier in it would affect anything.
BTW, the proper fill quantity now has been changed to 200ml from dry or 180ml on a refill.

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Jack - you might check at LandRover dealers. I believe I've heard they use it in their gearboxes or differentials. And from what I heard it was fairly cheapish ($10/liter sort of price.)