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Transmission leak after service.

  • <i class="fa--xf fal fa-check "><svg xmlns="http://www.w3.org/2000/svg" role="img" aria-hidden="true" ><use href="/data/local/icons/light.svg?v=1789222567#check"></use></svg></i> Discussion starter Discussion starter johndeeredr
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Hypoid gear oil smells the way it does due to the high amount of sulphur EP (extreme pressure) additive in it. Hypoid oils are formulated not to foam up in gearboxes. I am fairly certain that leaks from the vents that some are experiencing are due to fill level and have nothing to do with oil weight. It could be that the transmission oil has not been fully warmed up and completely drained during service and when the new oil is put in the level is too high.
 
Exactly regarding the additives and gear oil.

I am of the same opinion on the fill and cautioned the dealer about it when I dropped it off this morning. Oil in the vent is not an issue caused by the vent unless defective and not venting as intended.
 
RockinThor said:
For sure transmission oil. Gear oil has a unique smell as you noted. It has less than 900 miles so very much under warranty (bought in Jan this year). Dropped it off again this morning.

They are either over filling it, didn’t install the vent correctly/damaged it during install, or there is an internal issue in the trans (missing baffle, etc). The vent was updated by BMW to a new P/N but unlikely the cause .
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Having replaced mine they would really have to try to break it on install ... it is a small soft rubber gadget and really hard to break ... I have 2 possible causes ... #1 over filling, even just a little too much will make the oil drool out of that breather when hot ... or an oil that doesn't have enough anti-foaming agents ... that one IMO is less likely ... just my 2¢ ;)
 
Update for everyone’s info and entertainment…….they found a machining chip in the passage for the vent. Couldn’t remove it. BMW has authorized a full transmission replacement. Pros of this is if there were other chips or even this chip that are in there that messed anything up it won’t be a long term issue. Cons are the time it will take to get a transmission sent and installed plus the fact that the bike has to be disassembled to swap it.

Happy and not happy. The bike has now been at the dealer for service longer than I have had it. Also no BMW to ride. Very frustrating but hopefully this will fix it and not end up causing a host of issues from the R&R of the trans.
 
Thought about it but it is putting some oil on the tire, brake, and exhaust. Not a lot but enough that I don’t like it. Not to mention the puddles if I don’t put a pan or mat under it.
 
RockinThor said:
Thought about it but it is putting some oil on the tire, brake, and exhaust. Not a lot but enough that I don’t like it. Not to mention the puddles if I don’t put a pan or mat under it.
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Some news paper and bubble wrap... Use the bubble wrap to wrap yourself up in the event the rear tire gets a little squirrelly... 🐿️
 
An update for everyone’s entertainment……after 400 miles or so the brand new transmission leaked. Definitely has to be an overfill. The dealer called BMW and ended up draining it and putting 1.25L in this time. After another 400 miles no drips. Unfortunately with all of the leaks wire wraps are still soaked and I can smell oil every time I ride it since I picked it up. Even today trying to wash the area where the oil was. Cool bike…had not been ridden today. Will see if it helped the smell at all when we get back from vacation.

I have also had multiple calls with BMW customer service. We will see where that goes but they were not able to speed anything up parts wise nor get the dealer technical help to my knowledge.
 
How much fluid did the Service Shop use in your transmission? It's only supposed to be filled with 1.15 L

Are they using the BMW G3 specific fluid?

Screenshot_20260805-060343.png
 
Of course I do. I was just checking my owners manual after seeing the 1.15L you referenced. My OM doesn't state how much it uses so i was not aware of the capacity.

I had to rely on them and obviously they were not aware which is very disappointing. Rest assured I will be doing my own maintenance from now on.
 
Star-Lord said:
1.15 L or 1,150 mL
1.25 L or 1,250 mL

Your service technician dumped an additional 100 mL into your transmission case...


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I do love that clip! :ROFLMAO: Says it all really. As a child I grew up using the ancient celtic system of measurement and can remember learning Napoleon's new fangled French system in school, which I now know as metric SI units of measure. Having ridden BMW motorcycles for 45 years I find discussions of quarts, gallons, cubic inches, degrees F, ft lb thingies, and other wierd base-60 stuff like seconds / minutes / hours compells me to reach for a calculator, but then I think about it for a nanosecond, then settle back to consume 375 ml of cold beer. In Australian units of beer measurement, 375 ml = 1 stubby.

One the other hand, only the Germans could dream up the need to measure 1.15 L (1,150 ml). I'm surprised it didn't come with a +/- 1.15 ml.
 
johndeeredr said:
Replace my transmission oil on my R1800B . Went for a couple hundred mile ride and noticed some gear oil on my garage floor directly under the transmission. But I traced the steam of oil and it appears to be coming from the top rear or the engine . It’s not coming from the driveshaft seal but above it behind the engine cowling . Is there a vent there? Maybe I overfilled it ? Not sure but would appreciate some advice . I had some Bel-ray 85 - 140 hypoid gear oil left over from my Harley Days. And filled with 1.15 liters. Or 50 .72 oz .
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Go back to 70w80 transmission oil and it will stop leaking...
 
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