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Transmission Fluid Migration

The Harley Davidson Milwaukee 8's issue of transmission fluid migration from the transmission housing into the chain case , in my opinion , is nothing new.
I have a 2013 Fat Bob (103 in³ ) and I started to experience this problem well over 18 months ago.
I checked my transmission fluid one day and it didn't even register on the dip stick. There were no traces of a leak on my garage floor or under the bike itself so I rang my local Harley Davidson dealership and told them what had happened . They advised me to bring the bike in so they could check the levels and top up accordingly (they did this free of charge).
They advised me to go away and bring it back 500 miles later .
After about 100 miles, I checked the transmission fluid and once again , it had dropped. I realised that I could not continue to ride until I had covered the 500 miles , so I topped it back up.
Another 100 miles and another drop.
All this time engine oil level remained normal so there was only one other place the fluid could be going !
I removed the chain case and a LOAD of fluid came out !
Next thing was to try and find out how it was getting in there !
I studied the illustrations in my manual and decided through a process of elimination that the fluid was most likely getting past the clutch pushrod.
I went for a long ride and checked the fluid when I had got home and after the engine had cooled , only to find that there had been NO fluid loss at all !
It was now obvious that the problem was occurring during the time my bike was in its shed .
Since I had another small bike to squeeze in the shed alongside the Harley , I would store the Harley with the steering turned fully to the left with the bike resting on the twistgrip against the inside of the shed.
The transmission never lost another drop of fluid after that day !
My assumption is that knowing the chain case relies on the clutch pushrod for vent to the atmosphere , by leaning the bike to the right instead of on the jiffy stand , the right hand end of the pushrod is immersed in the transmission case's lube oil. When the air in the chain case cools after a ride , it contracts and so creates a vacuum which in turn 'sucks' fluid through from the transmission ! The transmission case , as we know , is vented via its own breather pipe.
As weird as this sounds , I can't see any other explanation !
Regards.
 
This whole issue is baffling and should not happen. Harley has been aware of this problem for a very long time and has been very slow to address and fix it. JMHO.
 
I've been following this topic and have heard a lot of conflicting reports. The most reliable reports seem to indicate that there may be a 4oz transfer which is nominal and that this happens on machines that have stage 4 upgrades... There are a lot of screamers and folks flapping their jaws over not much of an issue.

I'm not dismissing anyone's accounts or experiences but that is what I've read, seen in youtube videos, and been told by techs in both indy shops and MoCo Techs.
 
When I first approached the technician about this , he told me he had never heard of it !
Before I had noticed this problem , I had been keeping my bike in the previously mentioned position i.e. leaning slightly to the right for a considerable amount of time , possibly a year or so, but DEFINITELY long enough to empty the transmission completely if it were to lose fluid at a rate of 3 - 4 fl.ozs.per 100 miles , as mine was !
I think this re enforces my theory that once the fluid level drops below the end of the pushrod , the migration stops ! This is because when I realised that my transmission level was off the dipstick , the only way I had of checking how much (if any) remained , was to drain the remaining fluid into a graduated container.
This I did , and to my relief , some fluid had remained in there !
 
There are a lot of screamers and folks flapping their jaws over not much of an issue.

I guess if I shelled out 20+ grand i'd be flapping my jaws as well. I could understand if that's how they were designed but it was not.
1 fluid leaking into another chamber is a problem and the response from Harley has been pretty slow. JMHO.
 
Good thread, thanks for sharing. I'm keeping my eye on my levels for sure... 4,200 miles on it since purchase date of 02May and no problems yet.

Not everyone is experiencing this issue but enough so that Harley sent out a service bulletin to all it's dealerships advising them of the problem.
 
The major thing here is that if I'm correct , the migration stops when the transmission level falls to such a point that it is below the clutch pushrod irrespective of which side the bike is leaning .
The technician would probably drain the transmission and the chain case and not notice that there was too much in one and not enough in the other , but if ALL the fluid was being drawn out of the transmission , then when he removed the drain plug and nothing flowed out , THEN alarm bells would ring !!
 
Too bad there is no fix for the 17's and 18's. 18k on My 17 and I noticed gear grinding when shifting on occasion,Checked fluid and just touching bottom of the stick.Added fluid ,no more grinding.Warranty is over in 30 days,so I bought a service contract because I have had too many problems in the last 2 years. Like melted "plastic" intake manifold!!!!
Never bought a service contract on anything I have owned before.
 
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