Tiny metal flakes on the drain plug -- should I be worried about my transmission?

AntonLargiader said:

Well, you're describing transmission failure with practically every sentence you write. The worst one I saw had the owner (passing through) flying home to Canada while I trailered his bike from his motel to my shop. Maybe yours will go a while before you get to that point, but I sure can't predict for how long.

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Yeeeeeowch.

So I need to open up the transmission and address that input shaft gear and bearing ASAP...or just find a replacement transmission?

With only 36k miles on mine and the used ones I can see on Ebay having either unknown mileage or double what mine has, I'm leaning towards soft rebuild. Ideally replace all the bearings and seals and that input shaft gear. It'd be more expensive than a used unit but it might be the best option for what I have. Would give me the opportunity to do a spline lube and some other maintenance I had planned, too, like checking on the swingarm bearings.

I'll start tallying up how much the parts are going to cost. Ouch.

Edit: I just realized I hadn't been thinking about what the noise is and how it appears, and I've had a prior relevant experience.

Story time: I owned a 2007 Subaru Outback previously that would make a very similar whining noise that varied with speed -- its center differential had a failed carrier bearing, and that was the culprit. When I opened up the differential case and pulled the diff itself out I discovered that a previous owner had welded the center differential closed in four places so that the power distribution between the front and rear axles was locked at 50/50. They were bad-looking welds, clearly done by some cheapo MIG gun, and three of them had already cracked. The bearing had enough play in it that I could feel it, but it wasn't horrendous compared to how loud the noise was. What I suspect is that the process of welding either toasted part of the bearing or the welder had used the bearing as a ground. Either way a dummy did it. Replacing the bearing solved the noise but I couldn't afford to replace the differential itself, as it was a $500 part. That worked well enough until I sold the car.

Based on that experience I've had with bearing noise, that input shaft bearing must be in pretty bad shape...yipes. I'll start getting hold of the parts as soon as I can.

If you find your input shaft splines are worn, I have a M94 shaft (23 21 2 345 512) in VG condition I'll part with. Also have other M94 internals as well
PM me if interested

GSAddict said:

If you find your input shaft splines are worn, I have a M94 shaft (23 21 2 345 512) in VG condition I'll part with. Also have other M94 internals as well
PM me if interested

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That's fortunate. I'll keep that in mind when I get my transmission out. Though I'm not sure how many of the parts are compatible with my M97 (I believe it's an M97, haven't checked the number yet but build date is 08/96).

I'm curious to know if you have the problem gear (#23212345502) lying around anywhere, too. There are not many places one can get hold of it other than BMW.

senseamidmadness said:

That's fortunate. I'll keep that in mind when I get my transmission out. Though I'm not sure how many of the parts are compatible with my M97 (I believe it's an M97, haven't checked the number yet but build date is 08/96).

I'm curious to know if you have the problem gear (#23212345502) lying around anywhere, too. There are not many places one can get hold of it other than BMW.

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I do, Z=20, face is in good condition as well
Trans serial # 0003171 DAG
I do not have the build date

I gather that in this condition, the gear and bearing outer surface face are rubbing. Is it the gear that has moved, or the bearing, or something else happening like the whole shaft moving??

PGlaves said:

I gather that in this condition, the gear and bearing outer surface face are rubbing. Is it the gear that has moved, or the bearing, or something else happening like the whole shaft moving??

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Design issue.
Anton explains it very well.
http://largiader.com/tech/oiltrans/m97.html

GSAddict said:

Design issue.
Anton explains it very well.
http://largiader.com/tech/oiltrans/m97.html

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Thanks

Apologies for the poor picture quality, but when I swapped to the Castrol transmission oil I took a picture of the rag I used to wipe the transmission plug magnet.



Doesn't look like any long stringy bearing cage pieces to me (yet) but I'm no expert. This much didn't appear in just 40 miles, mind you. I just didn't realize during the previous change how deep the area around the magnet is and hadn't wiped it out thoroughly.

Whoops, that wasn't the picture I wanted but I'll leave it up. Here's the other picture which gives a more clear idea of the color of the sludge and the quantity of sparklies:

So I was perusing Youtube videos trying to get an idea of what typical Oilhead transmission noise is like, and I found this one.

https://www.youtube.com/watch?v=yZrvBF5F51w

My bike sounds pretty much identical to this R1100RT. 1st and 2nd gear have a significant whine, but it quiets down a lot in the higher gears. I can even hear the increase in volume and change in pitch when the rider decelerates in 2nd gear. The big clunks when shifting also sound identical to mine.

Folks with a lot more experience with more bikes than me, are those all normal Oilhead noises?


I'm not trying to get out of working on my transmission, mind you. Brown transmission fluid isn't good regardless of noises.

senseamidmadness said:

Folks with a lot more experience with more bikes than me, are those all normal Oilhead noises?

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Yes.

With the proper technique, the "clunks" can be minimised. Preload shifter, fan clutch lever on upshifts. Full pull on clutch lever and blip throttle on downshift.

senseamidmadness said:

I'm not trying to get out of working on my transmission, mind you. Brown transmission fluid isn't good regardless of noises.

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Another point to note. And I am not sure of the years but when BMW went to using greased, sealed bearings in the Oilhead transmissions a funny thing sometimes happened. People (owners mostly but a few dealers too) would use a synthetic gear lube. And when next checked the oil was brown. The synthetic lube was working past the bearing seals and washing out the grease. The bearings were still lubricated, but with gear oil like in the old days, but the washed out grease turned red, or yellow gear oil brown. One guy was so concerned at the start of an 11 day Iron Butt Rally that he had a replacement transmission shipped in. We found a garage and were prepared to swap out the R1100 transmission until he described his using synthetic gear oil for the first time in 40,000 miles. We convinced him it was washed out bearing grease and not to worry.

After my experience with “sealed bearings”, https://forums.bmwmoa.org/showthread.php?73076-Rear-wheel-bearings-on-a-F800GS,
I have lost faith in the concept.
OM

They are not sealed bearings

They are special TM bearings (aka clean bearings) and are lubricated by the oil.
The seals pass/filter the oil.
On the transmission case there is an oil channel to behind each bearing to allow for oil to flow through the bearing
The bearings are clearly marked as TM in order that they may be identified and not mixed up with conventional sealed type 2RS bearings that are permanently lubricated with grease.

https://www.nskamericas.com/en/prod...ansmission-bearings-low-friction-tm-seal.html
https://wenku.baidu.com/view/85dc0833f111f18583d05a6c.html

This design is now used in most every transmission, bearing life is many times longer than open or sealed bearings.

GSAddict said:

They are not sealed bearings

They are special TM bearings (aka clean bearings) and are lubricated by the oil.
The seals pass/filter the oil.
On the transmission case there is an oil channel to behind each bearing to allow for oil to flow through the bearing
The bearings are clearly marked as TM in order that they may be identified and not mixed up with conventional sealed type 2RS bearings that are permanently lubricated with grease.

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This is extremely useful information, thank you for sharing it! That picture of the bearing seats and oil passages is very telling.

I've been shopping for transmission bearings and thought I had the parts all picked. Really good to know that what I had selected are not the correct kind. I read through what seemed like a perfect transmission rebuild guide on ADVRider where one user rebuilt an R1100GS transmission and I had pulled some parts numbers from it; unfortunately all the bearings he selected were 2RS bearings. I wonder if his gearbox ever had issues down the road.

Though this also has me wondering, why is using dino gear oil so important if the bearings aren't fully sealed and are lubricated by the transmission oil? Is it just because of the theoretical issue with the ball bearings skating along their races instead of rolling?


On the subject of the brown gear oil: I have no idea what the previous owners were putting in, but mine has twice come out brown and burnt-smelling and the transmission plug is routinely picking up small metal flakes so I know something's not right and I will still be opening it up sometime soon to find out exactly what.

When doing a transmission I always end up using the OE ones (TM) as they are the only source.
BMW NA or Motobins UK
The BMW fiche describes them as clean bearings
Bearing houses don't stock them and some don't even know what they are.
They are very application specific.

I did find what appears to be an alternate and very common source for the 25x52x15 input shaft end bearing that the gear wears into -- according to this bearing house in the UK (https://www.bearings-online.co.uk/item/3938/NSK/TM205-A7-A-16-CG23-NSK-Gearbox-Bearing-25x52x15.html) manual transmissions in some GM cars use the same bearing and it has an ACDelco part number, 93368564. RockAuto carries that part for $35 each and tons of other GM parts shops have it in stock. Comes with a 2-year warranty!

I plan to order one of these from RockAuto and see what actually shows up, and will post pictures when I have it in person. It certainly seems possible to me that GM ordered a few hundred thousand genuine NSK TM205 bearings to use in their transmissions.
Shipping from RockAuto is $10 for the one part, unfortunately, so it'd be best to order it with other stuff, but it probably won't take a month to show up like a BMW order will.

Edit: I also found an Ebay listing that seems to further confirm the part being identical -- some excellent pictures that show a genuine NSK TM205- marking and "POLAND" along with the GM part number. https://www.ebay.com/itm/363169224771?chn=ps&mkevt=1&mkcid=28

senseamidmadness said:

I did find what appears to be an alternate …….

I plan to order one of these from RockAuto and see what actually shows up, ……..
Shipping from RockAuto is $10 for the one part, unfortunately, so it'd be best to order it with other stuff, but it probably won't take a month to show up like a BMW order will.
."…"…………

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FWIW, I order the Mahle oil, air, and fuel filters for my Oilhead from RockAuto. I usually order a year of maintenance parts in one order which brings the shipping cost down to a fairly reasonable per item cost. I order my Airhead maintenance parts with the same order.

m_stock10506 said:

FWIW, I order the Mahle oil, air, and fuel filters for my Oilhead from RockAuto. I usually order a year of maintenance parts in one order which brings the shipping cost down to a fairly reasonable per item cost. I order my Airhead maintenance parts with the same order.

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That's useful to know. I was also able to find that they've got plenty of suitable alternator belts and spark plugs and bulbs. Considering what I have been paying for individual maintenance parts on Ebay, I may end up copying your practice.

Edit: Removed this because I'm going to make a new thread about it.