Join Date: Oct 2010
Location: Oakland, CA, USA
tracking down oil leak on transmission
I am in the process of rebuilding my 85 k100rs and am currently trying to track down the source of a slow oil leak that has accumulated on the top of my transmission. The photos show the results from at least 40k miles and at least 10 years. It never dripped oil. The oil "stain" shown in the photos is the extent of it so, while it is large, I assume the leak is slow.
As you can see, the clutch area and the mating surface to the intermediate housing are clean so the oil is not coming from there. The blurry photo shows the intermediate housing. On the intermediate housing the oil is only within the cavity in which the alternator and starter sit. The outside of the intermediate housing and its connection to the engine are very clean all the way around.
To me, it doesn't appear to be coming from the connection areas of the starter of alternator.
I am guessing that the gear oil is coming out of the plastic cap on the top of the transmission. Strangely the cap itself is very clean but I can not think of any other source.
Any comments are appreciated but my questions are:
Has anyone else experienced leakage from this hole beneath the cap?
Is this cap some kind of breather hole that has a normal amount of fumes escaping that might accumulate like this over time?
Should I just clean it off and then keep an eye on it or is there any reason to open up the transmission and look deeper?
thanks as always. This forum has been a great find.
Last edited by kringb; Dec 2nd, 2010 at 1:55 pm.
Reason: added photos