Final Drive Viscosity?

deilenberger said:

Just a FWIW - I went back and looked up my service invoice for my 600 mile service. It lists 07-51-0-394-082 75W90 GL5 - which if punched into Max BMW's part lookup - http://www.maxbmwmotorcycles.com/fiche/searchbypartnumber.asp?PARTNUMBER=07510394082 - ie: QT 75W90 SYN GEAR OIL GL5

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And unless I have the long list of conflicting dealer quotes mixed up - Max's is one of the ones that said BMW didn't have a 75w90 synthetic oil.

Just another FWIW, I monitor the temperature of my final drive after rides and log it. On average, the FD on my R1200GSA runs 30C over ambient while the transmission runs 80C over ambient.

ssls6 said:

Just another FWIW, I monitor the temperature of my final drive after rides and log it. On average, the FD on my R1200GSA runs 30C over ambient while the transmission runs 80C over ambient.

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Which makes it appear perfectly sensible for BMW to specify that a 75w140 GL5 gear oil is OK in a transmission and to not say the same thing for a final drive.

Which is what I have been trying to say and failing miserably at for about a year now.

deilenberger said:

Mark, where do you get the SAF-XO in Canada? It would probably be a tad less expensive to get it from Canada than the UK..

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My independent BMW Master tech used it for my FD fluid change in November 2006. Off the top of my head I don't know where he got it. I couldn't find it on Castrol Canada's website.

PGlaves said:

Which makes it appear perfectly sensible for BMW to specify that a 75w140 GL5 gear oil is OK in a transmission and to not say the same thing for a final drive.

Which is what I have been trying to say and failing miserably at for about a year now.

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I don't think most people understand how big a factor temperature is in the viscosity of an oil. I've run into folks that believe a 75w-140 gets thicker when it gets hot.

What I think the summary is:

RepRom recommends Castrol SAF-XO for the final drive which nobody seems to have or know a BMW number for

Hammersley fiche does not show a lubricant on their final drive drawing

Max's and Real OEM fiches show 33117695240 part number for 75W90 oil and nobody seems to have any

07 51 0 394 082 is the part number for a BMW 75W90 oil that is available and has been what at least some dealers are putting in final drives

Some dealers recommend and use 75W140 oil with no written documentation from BMW to support the use of that for final drives.

BMW says to change the FD oil once at 600 miles for 07 models to flush out some contamination that is a result of the manufacturing process but does not recommend changing it at all for 05 or 06 models (but lots of people are changing it anyway, but not based on any real data, because nobody has done an oil analysis showing the lubricant is failing)

BMW final drives may be failing at a relatively high rate, but nobody knows what the rate is or what the actual failure mode is.

SBWayne said:

What I think the summary is:

RepRom recommends Castrol SAF-XO for the final drive which nobody seems to have or know a BMW number for

Hammersley fiche does not show a lubricant on their final drive drawing

Max's and Real OEM fiches show 33117695240 part number for 75W90 oil and nobody seems to have any

07 51 0 394 082 is the part number for a BMW 75W90 oil that is available and has been what at least some dealers are putting in final drives

Some dealers recommend and use 75W140 oil with no written documentation from BMW to support the use of that for final drives.

BMW says to change the FD oil once at 600 miles for 07 models to flush out some contamination that is a result of the manufacturing process but does not recommend changing it at all for 05 or 06 models (but lots of people are changing it anyway, but not based on any real data, because nobody has done an oil analysis showing the lubricant is failing)

BMW final drives may be failing at a relatively high rate, but nobody knows what the rate is or what the actual failure mode is.

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Pretty good summary.

But, actually the failure mode of the old style drives is pretty well known. Failure of the crownwheel deep grooved ball bearing. The failure starts when small flakes of the hardened surface fracture off the race. Damage to the balls is next. This can sometimes be detected by finding the small siver flakes on the drain plug magnet. With continued use, further damage to the races follows. If allowed to continue, a ball jams; the seperator cage collapses; which is followed almost immediately by wobble and leakage.

What is not firmly established is the cause of the initial fracturing of the hardened race surface. I have my opinion. Others have theirs.

PGlaves said:

And unless I have the long list of conflicting dealer quotes mixed up - Max's is one of the ones that said BMW didn't have a 75w90 synthetic oil.

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Max is certainly the dealer that put 75W-140 into my final drive when my outer seal was recently replaced under warranty. I personally haven't queried Max about their knowledge of the existance of 75W-90 full syn, however.

According to the confirmation Max's sent me when I ordered my oil, they had 3 quarts of 75W90 synthetic oil on 10/17/07. It has the ... 082 part number.

I had the FD on my 2006 RT replaced under warranty in July. I was on a long road trip at the time, so a friend of mine e-mailed me the wording of a BMW US service bulletin relating to the exact type of failure I experienced. I am copying it below. Note that in this bulletin, BMW US "highly recommend using BMW Super Synthetic Gear oil. 75W 90, P/N 07 51 0 394 082".

Here is the bulletin:

BMWMotorrad
USA
Service Information Bulletin
Subject: Bearing play at the rear wheel drive
Model:
Details:
Aftersales
Solution:
Dealer Operation/
General Manager
Sales-
Motorcycles
Sales -
Used Motorcycles
Business Manager
(F&I)
Service Parts & Accessories Administration
Date: February 2005
Bulletin #33 001 05 (011)
Source: 33 74/2004
BMW Motorrad USA Service and Technical
Contact: Respective Aftersales Business Consultant
R 1200 GS
1: In the rear drive of the R 1200 GS the ring gear is supported by two types of bearings:
one floating bearing and one fixed bearing without preload. Inherent in this design
is a small amount of bearing play at the rear wheel. With all components manufactured
and assembled to stated tolerances it is possible that play in these bearings can be felt
and measured at the rear wheel. This type of bearing play has no effect on motorcycle
handling or on the durability of the bearings.
2: There is a possibility of play developing between the splined wheel flange (P/N 33 17
7 668 659) and the axle tube of some motorcycles manufactured prior to 08/2004, US
VIN# ZL 76187.
1: In the event of a customer complaint, an inspection and measurement of rear wheel
bearing play is to be performed as described below. With cold components the total
play (back and forth travel) allowable at the wheel rim edge is 1mm(maximum). Refer to
the R 1200 GS Repair Manual CD for measuring procedures as well as temperature definition
of "cold components". Replace the entire rear-wheel drive assembly if the play
exceeds specifications.
2: If the complaint is "bearing play at the rear wheel" you must first check that the
splined flange is secure before performing the measurement noted in point #1. When
rocking the rear wheel back and forth, you must first make sure there is no movement
between the wheel flange, the rear wheel and the axle tube.
If play is noticeable between these components you must replace the entire rear wheel
drive assembly (complete with flange). Replacing the splined wheel flange only will not
solve the situation, because in all probability the splines on the axle tube will have suffered
some degree of wear as well. If you are in doubt, you are requested to contact your
respective Aftersales Business Consultant.
Warranty: Covered under the terms of the New Motorcycle Limited Warranty.
Important Note: Screw 1 is a drain
plug for repair-related oil changes; it is
not for checking the oil level. When filling
the rear drive assembly with oil,
pour in the defined quantity (0.25 l for
initial fill, or 0.23 l for oil changes)
through the bore for the ABS sensor.
We highly recommend using BMW
Super Synthetic Gear oil. 75W 90, P/N
07 51 0 394 082

Bingo! We have a winner.

Everybody whose dealer told them BMW doesn't have a 75w90 synthetic oil should ask them if they ever saw Bulletin #33 001 05 (011).

PGlaves said:

Bingo! We have a winner.

Everybody whose dealer told them BMW doesn't have a 75w90 synthetic oil should ask them if they ever saw Bulletin #33 001 05 (011).

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Is this, and other bulletins to which you refer, publicly available anywhere? If not, how is it that you have access to them? Are you a BWM dealer mechanic?

The total lack of official documentation on this topic that is available to owners is frustrating. Forget the Owner's Manual -- its useless in this regard.

Even when one buys the $125 offical BMW REP-ROM Manual, the final drive lubricant specified is Castrol SAF-XO -- a product that BMW NA does not market, and is not readily available in the US; however, BMW NA does market Super Synthetic Gear Oil, in either 75W90 or 75W140, that has NO OFFICIALLY DOCUMENTED APPLICATION in any BMW motorcycle based on any documentation that BMW makes available to owners.

TR250Tom said:

...I'll switch to RedLine 75W-90NS in the final drive "someday", ...there's an interesting comparison here that shows the properties of RedLine brand 75W-90NS and 75W-140NS. They have similar pour points, but by 40 degrees C the -140 has nearly twice the viscosity of the -90. I like this more than the data sheet for the Castrol SAF-XO here because it's an apples-to-apples comparison of two varieties from the same manufacturer.

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In this Amsoil Gear Oil White Paper, Redline 75W90 was found to be best in one test, "out of spec" in another test, and totally failed other tests.

http://www.synthetic-oil-tech.com/Gear Lube White Paper.pdf

PGlaves said:

Bingo! We have a winner.

Everybody whose dealer told them BMW doesn't have a 75w90 synthetic oil should ask them if they ever saw Bulletin #33 001 05 (011).

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I remember that bulletin and my dealer had one of those loose spline FDs. I didn't remember the reference to the gear oil, but that must have been where I read it. Instead, I thought that I read the gear oil recommendation in the FD oil change bulletin.
That "White Paper" test looks pretty good for the Amsoil synth. I wonder about the "long drain" (long time between drain and refill...lifetime?) spec for the Castrol SAF-XO. Just what makes a oil long drain? Which one of those tests would indicate a long drain oil?

gulfcoastbeemer said:

Is this, and other bulletins to which you refer, publicly available anywhere? If not, how is it that you have access to them? Are you a BWM dealer mechanic?

The total lack of official documentation on this topic that is available to owners is frustrating. Forget the Owner's Manual -- its useless in this regard.

Even when one buys the $125 offical BMW REP-ROM Manual, the final drive lubricant specified is Castrol SAF-XO -- a product that BMW NA does not market, and is not readily available in the US; however, BMW NA does market Super Synthetic Gear Oil, in either 75W90 or 75W140, that has NO OFFICIALLY DOCUMENTED APPLICATION in any BMW motorcycle based on any documentation that BMW makes available to owners.

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BMW usually publishes pretty thorough specifications for everything. What makes the new style final drives a bit odd is that at the time the bikes came out - books published - manuals written - the wisdom was that the units were lubricated for life. Thus, more or less a void in information as to what they used at the factory.

Then they changed their minds about the new style final drives and needed to tell their dealers what to do about it. They do that with service bulletins. Some dealers file them neatly in 3 ring binder books. Some seemingly don't open the mail, or they throw them in a drawer. Or the service manager files them but doesn't pass the info on to the techs who actually do the work.

It is not unusual for BMW to specify European products for which BMW USA needs to find equivalents. Welcome to the global economy. When BMW publishes a spec for 75w90 wt. GL5 rated gear oil, equivalents are easy to find. When they say Castrol SAF-XO by name somebody has to figure out specifically what that is. It is in fact a GL5 rated 75w90 wt synthetic gear oil. Nothing more - nothing less.

As for the public availability of service bulletins: BMW doesn't generally distribute them except to dealers, their tech reps, etc. They are considered proprietary. If you ask, however, many dealers will provide bulletin information to you. If I patronized a dealer that wouldn't share authoritative information as to how I should take care of my bike I'd find another dealer. But I never walk into a dealership in attack dog mode either.

For the new model final drives there are at least two bulletins. One issued to address what to do when play is detected in the final drive, and to explain what normal play is. And one to address the changing of gear oil at 600 miles.

The one addressing the change of gear oil specifies Castrol SAF-XO. The one from 2005 about play recommends the use of the BMW synthetic 75w90 GL5 rated Gear Oil packaged for and distributed by BMW Motorrad USA.

Since both of these bulletins reference GL5 rated 75w90 wt oil - one only by name, and the other by grade and weight - there really is no doubt what BMW intends to be used in these final drives - GL5 rated 75w90 Synthetic Gear Oil - except in the misinformation apparently put out by Customer Service rep's and some dealers who didn't do their homework.

Which is why I've been pleading for folks to see it in writing. Unfortunate, but true. The "opinions" of some dealers, just like some list posters, some of the time, just can't be relied upon to be correct.

For my columns in the ON I try very hard to get it right or not print it, but I've been wrong a time or two, too.

I just had my 600 service done at my dealer on my 07 RT and they did not change the final drive oil. I just contacted BMW NA and they were totally useless. The rep said that they don't have access to service bulletins and I should contact my dealer. I'm going to give them a call as soon as they open.

gulfcoastbeemer said:

In this Amsoil Gear Oil White Paper, Redline 75W90 was found to be best in one test, "out of spec" in another test, and totally failed other tests.

http://www.synthetic-oil-tech.com/Gear Lube White Paper.pdf

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Interesting reading! It certainly looks pretty legit, but the cynic in me wants to point out that the author of the report (Amsoil) is hardly unbiased. Agreed, we are told that the performance tests were conducted by an independent (but unnamed)laboratory, but does this ensure that Amsoil didn't provide "doctored" samples? Physical tests were conducted by Amsoil in-house. I am only jumping to Red Line's defense because of the potentials for bias and distortion in this kind of report.

The two tests where Red Line falls out of spec. are low-temperature viscosity, and foaming. Failure at -40C is not relevant to MY motorcycle riding habits. Admittedly, foaming is of much greater concern. However, of the 14 oils tested, I count 8 that failed this test. Can it be that the foaming test does not accurately reflect real-world conditions?

I note the Red Line stands head and shoulders above the rest in the Falex Extreme Pressure test. That test might be one of the most relevant (along with the 4-ball wear tests) of all the tests conducted.

And finally, the numerical summary uses a flawed methodolgy to assign scores. Simply assigning an integer rank to the results of each test greatly distorts the outcomes. Case in point is the 4-ball wear test. The very best score (.423mm) is only about 22% different from the very worst score (.516mm) yet the worst performer is assigned a summary rank that is 1400% worse.

I don't think there's anything wrong with the Amsoil gear lubricant; but these highly technical and offical-looking test reports remind me of the kind of data routinely published by the K&N Filter company. They just overwhelm non-technical type people with data that looks so official that it must be.

I contacted my dealer and the service manager insists that they changed my final drive oil. I said that it wasn't on the invoice. He said that it was on the mechanic's check off sheet. He said that they put in GL5 75/90 and because its in barrels that sometimes the mechanic dosn't write on the invoice that they added the oil. I'm hoping at this point he's being honest with me.

glurkus said:

I contacted my dealer and the service manager insists that they changed my final drive oil. I said that it wasn't on the invoice. He said that it was on the mechanic's check off sheet. He said that they put in GL5 75/90 and because its in barrels that sometimes the mechanic dosn't write on the invoice that they added the oil. I'm hoping at this point he's being honest with me.

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Holy Batman, Batman. Now they have the 75w90 synthetic stuff in barrels!

PGlaves said:

Holy Batman, Batman. Now they have the 75w90 synthetic stuff in barrels!

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Translation for glurkus:

If they actually did change your FD oil, and used the stuff in the barrel, they did not use the lubricant recommended by BMW. As far as any of us know, the synthetic lubricant doesn't come in barrels. Thus, apparently, they used conventional gear oil.