In over my head with a Leaky Gearbox (Pics!)

[ddebonis]

Hi All,

I've been making good progress fixing up my bike: turning signal works, seat lock works... Next up was fixing the leak from the clutch boot on the rear of the gearbox. However, it appears that it's leaking from as many as 3 places. I haven't even checked the gearbox oil level--I could be in trouble... Take and look and let me know what you think. Keep in mind, my "garage" is a city sidewalk and I don't own any special mechanical tools (ex: torque rench). Should I just take it to the shop?

-Danny

CLICK ON IMAGES FOR LARGER VIEW.

My garage:
[IMG width="600" height="400"]http://i1253.photobucket.com/albums/hh587/ddebonis/IMG_0709.jpg[/IMG]

Leaky clutch boot. Do I just replace this or could more trouble lurk within?
[IMG width="600" height="400"]http://i1253.photobucket.com/albums/hh587/ddebonis/boot.jpg[/IMG]

Right-side view of oil under gearbox.
[IMG width="600" height="400"]http://i1253.photobucket.com/albums/hh587/ddebonis/rightsidegear.jpg[/IMG]

Left-side view of oil leaking from gear shifter input and the front/bottom of gearbox.
[IMG width="600" height="400"]http://i1253.photobucket.com/albums/hh587/ddebonis/oilspot.jpg[/IMG]

[Bengt_Phorqs]

First thing is to clean up all the grease and grime with some carb or brake cleaner.  The leak underneath the gear box could well be a leaky neutral indicator switch, not an uncommon problem.  The crud at the boot could be just crud.  It happens over time, but should not be ignored.  Do check your fluid levels and top off after you clean the crud off.

As for working on a sidewalk, I'd try really hard to find a suitable storage place to work, even if it means renting a storage unit short term to do the work.  A bike that nice sitting on a public sidewalk is an invitation to the larcenous crowd.

[ddebonis]

Thanks for your fast response.

I tried to clean a lot of the gunk off. The rear boot is definitely leaking -- it used to leave spots on the concrete. I suppose I should finish cleaning it all up, add oil and see where the leaks continue.

What oil should I use? Do I have to worry about it matching what's already in the gear box?

Do I have to worry about properly torquing the gearbox oil input screw?

-Danny

[Bob_Roller]

Have you tried tightening the clamp on the boot at the rear of the transmission ?

At least you know the clutch throwout bearing is well lubricated .

The second picture, with the oil that far forward, I would not be surprised to find either the rear main seal, or the oil pump cover o-ring leaking .

The third leak is your shifter shaft oil seal leaking .

The rear boot and the shift shaft seal are quick replace type items, the rear main seal and oil pump o-ring, require the transmission to be removed .

Before you do anything, like Bengt Phorqs stated, clean the entire area up and then look things over after a long ride .

[ddebonis]

Thanks Bob.

What oil should I use? Do I have to worry about it matching what's already in the gear box?
Do I have to worry about properly torquing the gearbox oil input screw?

[Bob_Roller]

Seeing as how you have no idea what oil is in the transmission, I think I would just get some Castrol gear oil and top off the transmission .

Just tighten the fill plug, get it snug, you are torquing a steel fastener into an aluminum case so don't get carried away with tightening it up .

[nhmaf]

Any hypoid gear oil like 80W90 would be fine - I wouldn't bother getting any fancy synthetic stuff at this point til you find out what is up..

[ddebonis]

Thanks.

Any advice on how to loosen the trans oil fastener? I can't get any leverage on it with my allen wrench. The gear shifter is in the way. To help, I wanted to move the footpeg bolt, but it is rusted shut and can't easily be loosened.

[Bob_Roller]

You can tap on it with a hammer .

[rwait]

Take your spark plug wrench and place it over the allen wrench to gain more leverage.  Gives you a larger surface to hold onto as well.

[ddebonis]

Take your spark plug wrench and place it over the allen wrench to gain more leverage.

Thanks! This worked. When I unscrewed the oil plug, oil started pouring out. The bike on a a fairly level surface. So, this is good news -- the oil was NOT low. Perhaps there's a little too much.

I got Coastal GL-5 80w-90 gear oil, which I can use the next time I change the trans oil.

Also got brake cleaner to clean everything off. Seems like nasty stuff. I am a little worried about it melting plastic/paint if I spray it all over the gearbox. I work in a usually windy area... so that doesn't help. Any tips on using this stuff safely? I was gonna try orange oil-based degreaser first.  

[montmil]

Like brake fluid, these aerosol brake/carb cleaner products can damage paint and plastic; some worse that others. I use them frequently but with caution.

Back splash, always a dangerous possibility, can really mess up your eyes so wear protective safety glasses. Thin latex gloves can help reduce skin absorption of the toxic chemicals. Think safety and no ciggy.

Some biodegradable cleaners -Simple Green and such- can do a good job for the initial de-gunking with a follow-on using the spray can for tiny crevices and such. Borrow your brother-in-law's toothbrush for detail scrubbing. Use the Simple Green to clean it a bit before replacing it in the rack.

Lots of newsprint/cardboard under the bike. You're going to have a real mess when you have finished.  

[steven m]

And resist the temptation to use a high pressure hose to blast away the goo.  You don't need water in your gearbox.  

[steven m]

Looking at your photos it appears you have a leaking oil pressure sender, the one on the left side of the block.  I had the same thing.  Replaced in 5 minutes and leak stopped.    

[montmil]

Looking at your photos it appears you have a leaking oil pressure sender, the one on the left side of the block.  I had the same thing.  Replaced in 5 minutes and leak stopped.    

It does appear to be some oil streaking in the OP switch area. Easy and not an expensive replacement.

The oil on the "rear shelf" in photo #3 is either the neutral switch gone really bad or a rear seal or both.

The shift lever shaft oil seal is an easy fix after determining which one of two seal sizes available from BMW that you have with your bike. Important to note how deep the original seal is set into the case and match that measurement when replacing the new seal.
   The shift shaft pulls straight out and the open hole becomes a quick drain for the gearbox oil. Oops! Lean the bike over to the right prior to removing the shaft and you will avoid a major mess; not to mention needing to top up the transmission oil.