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Oil Leak 2000 K1200LT out of Transmission housing

mslacool

New member
I have an LT that is leaking oil from what appears to be a crack in the transmission housing. I don't have a lift and so to track down what it was, I put it on the center stand, toweled off all the old oil I could and then ran the bike til I saw the source of the leak and what I saw seems strange but it appears that there is a lateral crack in the housing developing near the front of the transmission, behind the oil pan and that it seeps out and its so small that you can't see the flaw but you can see the oil seeping out slowly. The amount of oil isn't huge but it does drip wherever I go now. I don't think the bike is worth investing a new transmission or the extensive repair into, and it runs pretty flawlessly and the oil light has not been coming on. If I am right the transmission has to come out and either be welded or replaced or possibly someone can weld the developing crack while on the bike ? I am assuming that after the Tupperware is off and the centerstand is removed, it would be accessible. I don't have a lift and I am not a welder. So, drive it til it breaks and keep replacing oil and wiping up oil spots? Or is there better advise out there.?
 
I'm a bit unclear on exactly what you know?
Is there a crack in the tranny housing, or are you just suspecting there is because you have oil leaking?

In front of the transmission, and behind the engine is the dry clutch (located in a bellhousing). If oil leaks from the engine (rear main seal failure) or from the transmission (input shaft seal), those oils will sink to the bottom of the bellhousing and eventually leak out of the seams where the various housing join. These failures are common on the K bikes as they age. You can guess the source by smelling the oil: if you smell sulfur, it's from the gearbox. These leaks typically lead to clutch slippage when they eventually wet the dry clutch disc.

A cracked tranny housing is certainly possible, though I've not heard of this issue being common. My gut would tell me to give up on the "weld it" approach. I'd look at the used BMW sites for a used transmission.

The problem here, in any case, is the cost versus the value of the bike. I obviously don't know the condition or the mileage, or what the bike means to you, but LTs this age can be had for under $3k. The labor to replace a wet clutch is typically quoted at over $2000 by most shops, installing a new/used tranny would run even higher.

So crack or no crack, you have some tough figuring to do. Best solution I can come up with is to find a do-it-yourselfer who's willing to do the wrenching for you. That's likely the only way you can make the numbers work.
 
If the housing is actually cracked (a pic of the area would help, with crayon marking where the crack is) I would stop riding the bike. Something made the crack develop, and the forces on the transmission housing could make it spread and fail catastrophically, locking the rear wheel or at the very least dumping a lot of gear oil underneath it.
 
Thank you I did not know you responded but here is the update

I got out my tools, bought a used lift and my manual and dove in. I got the right side tupperware off to take a look at it and it seemed like there were two original leak sources, near the rear of the oil pan and at the rear of what I think is the transmission. it dripped to the ground in both of those places. I have driven it like that for about 2000 miles. i had originally thought one was simply blowing oil from the other. I could not reach the bolts that tighten the transmission or both of them so I took off the center stand and the side stand then carefully feel tightened the rear oil pan bolts and the lower two transmission rear bolts and fired up the engine in order to see if it worked in whole or part. The front leak near the rear of the oil pan seemed to have stopped. The leak that I thought was a cracked housing wasn't a cracked housing, it was just as you suggest, a leak at the very bottom of the seam or seal at the rear of the housing. To show my inexperience I did not know that seam existed til I got everything off cleaned it up and took a good look with a flashlight. I tightened the bolts as I said and have left it in that condition, seeking advice from various sources. I know the advice about the value vs the cost of the repair and while mechanical, I have no experience in this sort of stuff... I sort of go a bit, get some advice and go some more. At this point, I am fairly confident its no more than a leak and slow enough that I will just drive it and check the oil regularly. Its been reliable as rain for the most part. I broke a linkage but found a used one and replaced it myself about a month ago. I am curious as to whether I can do damage by tightening the rear transmission bolts more to help seal the leak or just let it go because of its age ( I don't mean break them, but I would have to borrow a torque wrench. All of this is happening away from my home at my condo garage in Phoenix so I really don't have my tools that I have in Montana.
 
a reply

If the housing is actually cracked (a pic of the area would help, with crayon marking where the crack is) I would stop riding the bike. Something made the crack develop, and the forces on the transmission housing could make it spread and fail catastrophically, locking the rear wheel or at the very least dumping a lot of gear oil underneath it.

I got out my tools, bought a used lift and my manual and dove in. I got the right side tupperware off to take a look at it and it seemed like there were two original leak sources, near the rear of the oil pan and at the rear of what I think is the transmission. it dripped to the ground in both of those places. I have driven it like that for about 2000 miles. i had originally thought one was simply blowing oil from the other. I could not reach the bolts that tighten the transmission or both of them so I took off the center stand and the side stand then carefully feel tightened the rear oil pan bolts and the lower two transmission rear bolts and fired up the engine in order to see if it worked in whole or part. The front leak near the rear of the oil pan seemed to have stopped. The leak that I thought was a cracked housing wasn't a cracked housing, it was just as you suggest, a leak at the very bottom of the seam or seal at the rear of the housing. To show my inexperience I did not know that seam existed til I got everything off cleaned it up and took a good look with a flashlight. I tightened the bolts as I said and have left it in that condition, seeking advice from various sources. I know the advice about the value vs the cost of the repair and while mechanical, I have no experience in this sort of stuff... I sort of go a bit, get some advice and go some more. At this point, I am fairly confident its no more than a leak and slow enough that I will just drive it and check the oil regularly. Its been reliable as rain for the most part. I broke a linkage but found a used one and replaced it myself about a month ago. I am curious as to whether I can do damage by tightening the rear transmission bolts more to help seal the leak or just let it go because of its age ( I don't mean break them, but I would have to borrow a torque wrench. All of this is happening away from my home at my condo garage in Phoenix so I really don't have my tools that I have in Montana.
 
a reply and thank you

I'm a bit unclear on exactly what you know?
Is there a crack in the tranny housing, or are you just suspecting there is because you have oil leaking?

In front of the transmission, and behind the engine is the dry clutch (located in a bellhousing). If oil leaks from the engine (rear main seal failure) or from the transmission (input shaft seal), those oils will sink to the bottom of the bellhousing and eventually leak out of the seams where the various housing join. These failures are common on the K bikes as they age. You can guess the source by smelling the oil: if you smell sulfur, it's from the gearbox. These leaks typically lead to clutch slippage when they eventually wet the dry clutch disc.

A cracked tranny housing is certainly possible, though I've not heard of this issue being common. My gut would tell me to give up on the "weld it" approach. I'd look at the used BMW sites for a used transmission.

The problem here, in any case, is the cost versus the value of the bike. I obviously don't know the condition or the mileage, or what the bike means to you, but LTs this age can be had for under $3k. The labor to replace a wet clutch is typically quoted at over $2000 by most shops, installing a new/used tranny would run even higher.

So crack or no crack, you have some tough figuring to do. Best solution I can come up with is to find a do-it-yourselfer who's willing to do the wrenching for you. That's likely the only way you can make the numbers work.


I got out my tools, bought a used lift and my manual and dove in. I got the right side tupperware off to take a look at it and it seemed like there were two original leak sources, near the rear of the oil pan and at the rear of what I think is the transmission. it dripped to the ground in both of those places. I have driven it like that for about 2000 miles. i had originally thought one was simply blowing oil from the other. I could not reach the bolts that tighten the transmission or both of them so I took off the center stand and the side stand then carefully feel tightened the rear oil pan bolts and the lower two transmission rear bolts and fired up the engine in order to see if it worked in whole or part. The front leak near the rear of the oil pan seemed to have stopped. The leak that I thought was a cracked housing wasn't a cracked housing, it was just as you suggest, a leak at the very bottom of the seam or seal at the rear of the housing. To show my inexperience I did not know that seam existed til I got everything off cleaned it up and took a good look with a flashlight. I tightened the bolts as I said and have left it in that condition, seeking advice from various sources. I know the advice about the value vs the cost of the repair and while mechanical, I have no experience in this sort of stuff... I sort of go a bit, get some advice and go some more. At this point, I am fairly confident its no more than a leak and slow enough that I will just drive it and check the oil regularly. Its been reliable as rain for the most part. I broke a linkage but found a used one and replaced it myself about a month ago. I am curious as to whether I can do damage by tightening the rear transmission bolts more to help seal the leak or just let it go because of its age ( I don't mean break them, but I would have to borrow a torque wrench. All of this is happening away from my home at my condo garage in Phoenix so I really don't have my tools that I have in Montana.
 
The cavity behind the engine and ahead of the transmission is the bellhousing or the clutch housing. It is a dry cavity. Fluid can leak into it from the transmission shaft seal at the clutch, or from the rear engine main seal. One would be stinky transmission gear oil and the other would be less stinky engine oil. Do not try to tighten the bolts any tighter. It won't accomplish anything and there is a risk of stripping threads.
 
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I hope this gets to you.

Doesn't the transmission and engine oil use the same reservoir and oil? I thought the oil lubricated it all. I think its engine oil and looks exactly like engine oil. I swap final drive oil but never transmission oil. I didn't even know they were different things... i better go read up as that never even occurred to me. I did work extra carefully on tightening the bolts, I know they can snap and so I am done on that forefront.



Paul
 
Doesn't the transmission and engine oil use the same reservoir and oil? I thought the oil lubricated it all. I think its engine oil and looks exactly like engine oil. I swap final drive oil but never transmission oil. I didn't even know they were different things... i better go read up as that never even occurred to me. I did work extra carefully on tightening the bolts, I know they can snap and so I am done on that forefront.



Paul

No. On that model there is engine oil (normally 20w50) in the engine and gear oil (80W90 gear oil) in the transmission separated by a dry clutch in the bellhousing.
 
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just watched the video.. live and learn swapping tranny fluid while I got her open

No. On that model there is engine oil (normally 2w50) in the engine and gear oil (80W90 gear oil) in the transmission separated by a dry clutch in the bellhousing.

Thanks
I will swap the tranny fluid while I got her open. live and learn. the leak is definittely ts engine oil. I am assuming I can just drive it til it breaks then let everybody fight over the parts?
Paul
 
Here's a couple links that will help you out:

A link to all BMW's owners manuals (covers all models)

Link to the K1200LT Repair Manual

There were some changes depending on your year/model - so double check before you dive deep.



I'd clean it all up, then go for a longer ride to see exactly what's leaking where. Side note: If it's your oil pan, it's not difficult to drop the oil pan and renew the make-a-gasket, it is almost 20 years old... Baby powder dusted over the engine afterwards can help you see fresh oil too.
 
Thanks
I will swap the tranny fluid while I got her open.
Paul

Here's the fill plug for the transmission.
The drain is below that position and I think it takes a 14 mm hex.
On the RS there's no washer on the drain plug and I'm guessing the LT is the same.

Trans fill plug.jpg
 
Thanks Replaced the tranny fluid, then decided to just tear off the whole thing

I have multiple little things to do so I pulled it all apart and off with the tupperwear. God, if there was a cheap alternative to the existing shock, I would do it now but everyone says that buying used is like getting the same thing you are replacing.
 
. God, if there was a cheap alternative to the existing shock, I would do it now but everyone says that buying used is like getting the same thing you are replacing.

When the rear shocks were worn out on our K1200RSs I replaced them with almost new take offs.
 
When the rear shocks were worn out on our K1200RSs I replaced them with almost new take offs.

That shock was '97 thru '03 LT only. Odds of finding a 16 year old take off is probably pretty slim. Buying a new (still available) one from the dealer for $1100 probably makes the most sense.





:dance:dance:dance
 
You may get lucky finding an unused BMW shock, but you're not really going to know what you're getting, and as Lee stated the shock is going to be 16+ years old (so the seal is holding up fine on the shelf, but what about when it's on the bike?).


Buying a new (still available) one from the dealer for $1100 probably makes the most sense.



I would go aftermarket for that price... you can get a brand new, fully-rebuildable front AND rear, with a 5-yr warranty for almost that price. (Just checked Pirates Lair - no affiliation)

Or find a used aftermarket shock and get it rebuilt. Either way, the bike is going to handle much better after a refresh.
 
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