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Discolored Trans. lube


dave sawyer

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1997 R1100RT, 133,300 miles. Mobile 1 75/90W since 12,000 miles.

Drained after 6700 mile Montana trip. Came out similar. This is fresh lube with 1000 miles.

Comments please.

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Looks like the dreaded 'chocolate gear oil' syndrome. Long story short, your rear input shaft bearing is failing and the grease seal has ruptured, contaminating the gear oil and giving it a characteristic brown color. Not an uncommon problem with an M97 transmission at high miles, in fact I'd even expect it. Send an oil sample to Blackstone to be sure, but I bet it shows high iron & chromium. If so, time to pull the tranny...

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Looking at the BMW shop and Haynes manuals, the rear input shaft bearing appears to be an unsealed taper roller bearing. Right/wrong?

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On the 1997 and later models all transmission bearings are sealed caged ball bearings. 1996 and earlier models used a tapered roller bearing on the input shaft and a combination of open and sealed caged ball bearings on the other shafts.

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Anyway to tell if maybe they stuck an 96 in my 97. Serial #, etc.

Probably with the chocolate color I already have that answer, eh?

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I must be missing something. Is there only one picture? Or are there two? The one I see looks like the gear oil sample I took from my tranny which tested fine. Here is what it loked like, very similar to the picture the OP put up.

 

dsc00003_1216496981.jpg

 

Then again, my computer has some image loading issues sometimes, and I'm probably missing the boat here. Please set me straight.

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Well it's always hard to tell from a picture, but basically what you drain out should be substantially the same color as what you put in (i.e., look like new gear oil.) A noticeably darker color is often the harbinger of a problem.

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Oil analysis discussion primarily involving a 96 RT transmission HERE. The anaysis is from Blackstone as I've been using their service for a couple of years.

I'm sure there are factory shops that do excellent work, but Anton Largiader is an independent who can take care of your trans in the least amount of time and well within the cost you would pay a dealer's service shop (not inexpensive no matter how you do it). He's about a 3 hr drive away, in Charlottesville, or will accept the trans shipped in and can ship it back to you. I drove mine down, watched him disassemble it as noted in this transmission thread, and drove back down to pick it up when he was finished. The wait was because my damage was not immediately apparent and a bearing set had to be ordered.

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To determine which transmission you have go to the "Anton" link in the reply above. From the page that opens go to "Back to Index" then under "Transmission, Clutch and Final Drive" go to "R1100 Transmission". There you will find out where to locate the serial number of your transmission and from that how to identify which one it is.

 

Ewell

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I have a riding buddy with an '02 1150RT who had this happen two years/30,000 plus miles ago. His tranny is still running fine. He changed the transmission oil until it cleaned up, and just continued riding. The bearing is lubed by transmission oil now, instead of the original grease.

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The bearing is lubed by transmission oil now, instead of the original grease.

Mere lubrication of the bearing is not the issue in this case. In the 1100 transmission (subject of the original post) a seal failure in the rear input shaft bearing is usually caused by failure of the bearing itself. If this is what has happened the problem will not go away, and if not repaired eventually a catastrophic failure will result.

 

BMW changed the design of the input shaft in the 1150 and it doesn't seem to be affected by this particular problem, so whatever happened to your friend's bike is likely a different matter.

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  • 4 weeks later...

Update on my transmission.

Took the trans. up to Anton at Va. Motorrad in Charlotesville for inspection/repair. Once inside it was found that the Input shaft gear had pounded itself into the bearing and broke the bearing seal releasing the bearing lube into the the gear box. That' what caused the discoloration.

And it turns out that this is a good thing. Had the lube not been discolored I wouldn't have known I had a problem as the transmission wasn't showing any other symptoms.

The gear isn't cheap at $240. With bearing and seals and 4 hours labor the bill came to a tad over $600. Less than I expected.

Anton has a small, cluttered shop on the back of his house. He's hoping to expand soon, but with the economy as it is he's waiting to see how things go.

That aside, after watching him work I was very impressed with the attention to detail. The shimming of these trans. is an art unto itself. I will be taking more work to him if needed.

I've enclosed a picture to show what went bad.

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Here's another picture of the bad gear and bearing. The previous picture was the new gear (left) and damaged gear.

You can see how the gear impacted the bearing, breaking the seal.

If not repaired the bearing would soon disintegrate causing a lot more damage.

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End result of discolored tranny lube being ignored (unfortunately, I was apparently the first to observe this symptom. Below occurred after 1K miles of additional hard riding.):

 

364423202_Yaghz-L.jpg

 

364423498_AVvzf-L.jpg

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Update on my transmission.

Took the trans. up to Anton at Va. Motorrad in Charlotesville for inspection/repair. Once inside it was found that the Input shaft gear had pounded itself into the bearing and broke the bearing seal releasing the bearing lube into the the gear box. That' what caused the discoloration.

Yep, happens all the time, and those of us who have been there before already knew exactly what you'd find after seeing that gear oil.

 

This is a pretty serious design weakness of the 1100 transmission. The helical drive gear directly contacts the bearing inner race and isn't even fully supported by the latter, and my theory is that the problem is greatly exacerbated by the wave washer installed in the later models which allows the gear to move back and forth on the shaft and slowly hammer the bearing to death. Some of us have removed the wave washers from a few transmissions and time will tell whether this has any positive effect.

 

In the meantime I would advise any high-miles 1100 owner to watch that gear oil color and also get an oil sample analyzed every once in a while (because the bearing wear can take one of several forms and isn't always revealed by gear oil discoloration.) If caught early the repair isn't horribly expensive but if you let it go... well, Michael's pictures tell the story...

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I had to do mine at the 100k time frame as well . It wasn't a big deal a lot of other bikes wouldn't even make it that far . If they do usually they need a clutch and clutch basket as well . Dave

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Anton Largiader

Dave,

 

SageRider's pictures show EXACTLY what was in that 'worst case' I was telling you about, where the guy was stuck and the tranny housing was trashed. When we opened the drain plug, at first nothing happened and then the oil very slowly came out looking like lava. "Niid so guet" in dialect.

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Anton,

My failure stranded me on the side of US50, "The Loneliest Highway" East of Ely.

I had just come off a high speed run between Delta Utah and the mountians west of the Nevada state line. Smelled gear oil. Stopped twice within a couple of miles but unable to find leak or other problem. When I stopped a third time, the clutch lever no longer actuated the clutch. Friction had melted the bearing for the pushrod, which had snapped. Tow time....

The gear oil that came out of that tranny was some of the most evil stuff I have ever smelled... Probably the only reason it wasn't solid crud was that it was synthetic gear lube. No varnish on the cases at all.

Rear case, input shaft, and all other bearings and seals were replaced.

About 100 miles later, the seal at the rear of the input shaft failed. Unknown to this day if we somehow screwed up in the rebuild (if so, multiple sets of eyes missed it.) or it was a defective seal.

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