Trans output shaft seal leak...

[rob1100r]

So my buddies 96 R1100R w/25K on her has developed this leak (more like a very slow drip). So I spend some time reading about it in this and other forums. I came accross a few threads where people talk about the compatability of the seals w/the use of Synth gear lube vs. Dino. The following link is one of a few a read..

 

http://www.bmwmoa.org/forum/showthread.php?t=32074

 

The user PGlaves typed something of interest, and I read similar in another thread. I mean, cmon! I love how the leak stopped after 100 miles, etc etc. I know he is also comparing it to the FD vs the trans. I'm just wondering if anyone on this board experienced anything like this, and did the 'dino' oil solve your problem? I for one am using Amsoil gear oil, with no leaks (yet!) but bike only has about 15 k on it (2000 R1100R) My buddy is quite the 'doer' and is getting ready to replace the seal come Nov. (along w/ the JL Paralever Bushing Upgrade Kit!) but is going to try this first anyway...Who here has run Synth w/o any leaking issues? The bike is 15 yrs old, seals will give up, maybe this is just a 'time' thing...?

[dirtrider]

Hi Rob

 

It sure isn’t conclusive but I have had many trans and final drive “seeps” stop or reduced by switching gear oil types or brands. I had an old Honda that it’s final drive seeped from the time I started using Mobil 1 until I switched back to conventional gear oil. Same with my 1100 and 1150 BMW. The pinion seal would always seep slightly when using unlevel synthetic gear oil. A switch back to conventional would usually stop the seep.

 

Now don’t take this to mean that synthetic gear oil is somehow thinner or has smaller oil molecules. It really isn’t the synthetic or conventional aspect of the gear oil it has more to do with the amount of seal conditioner in the gear oil. Keep in mind the most synthetic gear oils are developed for usage in modern automobiles that spec the gear oil for high fuel economy and low drag numbers. In a lot of cases these modern vehicles have very high quality low drag seals. They can’t get those low drag and high mileage figures if the seals are dragging so the use of seal conditioner in the better synthetics are usually at or near the low side of adequate.

On the other hand most conventional gear oil are not speced out for modern high fuel economy vehicles or low drag concerns. Most conventional gear oil’s have a rather high concentration of seal conditioners therefore the less chance of seal seepage.

 

If the trans vent isn’t plugged or trans isn’t overfilled on that motorcycle then by all means “try” a conventional gear oil to see if the oil seep stops. It only costs a little time and a quart of gear oil to see if it makes a difference.

 

[scout6]

We have a similar situation with an experienced Honda Shadow. Synthetic oil actually squirts out the input shaft seal within moment of fill. Regular old Dino will begin to push past this poorly designed seal about once every other year.

[4wheeldog]

In the case of the '96 with 25k, it is probably more a case of the seal drying out from lack of use than the variety of lubricant.

 

My '02 has had synthetic in the tranny and final drive for 60k plus with no discernable leaks......Other than the warranteed final drive failure.

[philbytx]

Rob,

FYI - I run synthetic oils and greases in our cars, bikes and trailer.

 

My 2000R was low mileage (6750) when I bought it and it already had a rear seal weep, so I used a mix of 75/25 Mobil1 75w140 and Lucas Transmission Fix. .

Cured it nicely....also tranny shifts better too !

I previously used the Lucas stuff successfully in my BMW E34 cage manual transmission to stop a rear seal leak.

 

Go cheap first

[Jerry Johnston]

My 96 with 60k mi. is using synthetic oil and has NO leaks. Also hasn't been rode much the last 3 years.

 

[BrianM]

97 with 105,000. Mostly used Redline shockproof gear oil with no leaks.

[rob1100r]

I guess as the old saying goes, you dont use it you lose it! So by not riding it, the seal may have stayed dry for too long, as in philbytx's case, and like 4wheeldog said (lack of use), as well as many other people have said about these bikes. But that is probably the case with any 'mechanical items', they sit around and go to $hit. Being that my bike sits around too much I can expect the same . Yeah I know, shut up and ride it! He put different fluid in last night, raining right now, will ride it during the week. We're going on a good run next Sunday

[AndyS]

Which seal is it?

The input seal or the large output seal?

 

Andy

[rob1100r]

Without pulling the swingarm off, all we can see is some gear oil around the boot (up front of course) Input or output seal? Not sure. Is one more prone to fail than the other, under these 'specific' conditions?

[AndyS]

That kind of answers the question.

The oil is coming from either the output of the gearbox (doubtful and fairly uncommon)

or

The Input seal to the FD (probably and VERY common). Thgis is almost a case of They All Do That....at sometime in the bikes life.

 

Remove the band securing the rubber gaiter from the FD to the swing arm. Using a torch and mirror (or whatever) take a good look to see if oil is running down from the gearbox end - this is very unlikely.

If it is just from the input to the FD, give the area a good clean and reinstall the gaiter.

Check the level of the FD and just keep an occasional eye on it.

These leaks will come and go but generally are things that you can live with.

Even if you replace the seal there is no guarentee that it will not weep again at any variable time in the future.

 

Andy

[rob1100r]

The oil is coming from either the output of the gearbox (doubtful and fairly uncommon)

or

The Input seal to the FD (probably and VERY common). Thgis is almost a case of They All Do That....at sometime in the bikes life.

 

Your probably right, that is what I see more of as I read about this particular leak. We'll probably pull the boot off and take a peek soon.