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Primary Oil Leak

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Here's a tip posted by "TQ" that happens quite often and is mistaken for a primary leak when it was the vent hose on the transmission causing the oil to mist onto the inner primary and appear as if it was leaking.

Before you do all that, is there a small "j" shape black tubing on a nipple that comes out of the trans top cover or the end of the trans case behind the inner primary.
This is the trans vent.
Mine was spraying a fine mist of trans fluid on the back of the inner primary that made me think there was a leak in the primary. It would take a few days to a week after thoroughly cleaning the bike for the drip/leak to show up. After going through. I finally figured out it was just the vent tube!!! Very frustrating.
To fix it, I got a couple of feet of black tubing from the auto parts store and routed it back over the starter to the other side of the trans and down towards the ground. Pix attached:
 
Finding an oil leak

Recently I noticed a small oil stain on the concrete garage floor under my 1995 Electra Glide Classic (FLHTC). The stain was about 3" in diameter.

Upon investigation I thought the leak was from the inner primary chain case seal since the lowest and farthest back bolt was dripping, so I pulled the case off and changed all the seals and gaskets. However, when I put the bike on the kick stand I noticed that there still was something leaking so this is what I learned after all kinds of further investigation and repairs.

- To test for a leak location, remove the entire primary chain case and wipe dry. Verify that the transmission fluid level is full. Then put the bike on the kick stand and let it sit overnight. If the main transmission seal (which is about 3" in diameter) or the shift lever seal (about 3/4") are leaking you will see this in the morning since the lean angle of the bike when on the kick stand will put transmission fluid against these seals. Probably best to replace these seals once you get the chain case off.

- Transmission fluid, which is the same as the primary chain case lubricant, is, and remains, almost clear with a light green/gold color. Engine oil is almost always black in color once it is run in an engine for a short time. You can look at the dip stick to see the color. If your leak is black in color then it is engine oil. In my case, the oil on the floor was transmission fluid.

- The leak appeared to be coming from the inner primary chain case gasket because the bolt that is the lowest and farthest back was dripping but it turned to out to be the main transmission seal (which is about 3" in diameter). The fluid from this leak was dripping down onto the bolt so it looked like the inner primary gasket was leaking but it was not.

- Black RTV silicone needs to be used to coat the bolt threads and pads as described in the Service Manual. Note that RTV stands for Room Temperature Vulcanization which takes about 24 hours so don't ride the bike or put chain case lubricant in the bike for 24 hours.

- You can add Kent Moore Florescent Oil Additive J28431-1 to the transmission fluid and then run the bike prior to removing the primary chain case and then observe the seal areas with a LED flashlight.
 
I just checked out a recent model year (96ci w/OEM 6-spd) RK, and noticed that the tranny vent tube on that bike is even worse than the one I had on mine! It is a small, short (about 2") piece of formed tubing that rises MAYBE an inch above the cover and then turns to vent ON TOP of the tranny case!! Any little burp of tranny gear oil or mist is gonna make a mess on the top of the tranny case that is hard to clean! I would definitely fix that on a proactive basis.

TQ
 
I have a 92 Softail heritage and I have this for a while now, suddenly one day I notice a drip of oil in my garage and its coming below the primary so i took it to Hardtailz (H.D Sertified repair shop)for repair. After a few weeks of driving just around town I notice that the leak is gone, then one day I took it for a 45 min drive, park my bike at work thinking that everything is fine, when I came back 2 hrs later there was a pile of pink oil on the ground and not only that, while I was driving it back home my bike feels like it is struggling to hit 70mph? I return my bike at the shop and they reseal everything, they said everything is fine and advise me to take it for an hour drive and see if the leak will come back....guess what?? after an hour of driving, park my bike in the garage, waited for an hour and the leak is still there. Anybody in this forum, pls advise! Thanks All!!
 
Deni,
From the photo I see that you pulled the input shaft out. Did that come out this side? what holds it in on the other.

I think the needle bearing seal is out on mine. I thought about pulling the sleeve but would have to buy the tool.

Thanks
 
outlawspeeder said:
Deni,
From the photo I see that you pulled the input shaft out. Did that come out this side? what holds it in on the other.

I think the needle bearing seal is out on mine. I thought about pulling the sleeve but would have to buy the tool.

Thanks
Click to expand...

You really need the correct tool to pull and reinstall the the bearing inner race from the mainshaft
then if you use a small drill bit drill a small hole in the metal part of the seal and screw in a self tapping screw then pull on the screw to pull the seal out
clean off both inner and outer surfaces that the seal sits on and fit a new seal i drove the seal in using some rigid plastic pipe long enough to go past the end of the mainshaft
then refit the bearing inner race pay attention to the correct distance from the seal

Brian
 
A really good way to tell if the leak is coming from the primary or the trans, get some florescent additive from a auto parts, wash the underside of the bike best you can and put a little dye in the primary, run the bike then check it with a blacklight, it hard to tell where a leak is coming from when it's behind the primary, the dye helps.
 
I have a leak coming from that general area also behind the inner primary ('01 FLHRC). Really only noticable after riding and the oil has sprayed over my rear pipe and the ol' lady's pants leg. When it sits afterward it only drops a spot the size of a quarter.

Thanks for the dye idea. Would really like to know where the leak is coming from before I tear it down.

In passing, it was suggested to me the air cleaner (stock) may be the culprit... that it is not allowing the case to breathe, and a K&N high flow would solve the problem. Possibly any truth to this?
 
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