M8 trans oil migration
Grand HDF Member
Joined: Nov 2017
Posts: 4,251
Likes: 3,134
From: Texas
As far as I can tell, no Softail owner has ever reported this issue on this forum. Transfer is not an M8 issue, it is a Touring bike issue. Softails don't transfer, and they don't appear to sump either.
Road Captain
Joined: Jan 2019
Posts: 607
Likes: 143
From: Hilltown
The trans main shaft is hollow and used for two things....
One, the clutch pushrod travels between the clutch cable/hydraulic actuator under the trans side cover to the the clutch in the primary, via this hollow shaft.
Two, the shaft is not sealed. It has a secondary job of allowing the pressure to equalize between the trans and primary, and vent out the trans vent, if necessary.
The only way you can lose 8oz of trans oil and have it show up in the primary, is via this shaft...... that much is agreed on. Now why/how it is doing this is an ongoing discussion...
The scary part of this issue is it is unknown how many bikes are affected. It is NOT an issue on all bikes. The transfer rate appears to be dependent on how hard you run the engine, higher rpms have been shown to increase transfer. If you don't look for it, most people won't know they have it...
For example; you ride easy between service visits. You may only have 2-3oz of transfer. The service tech dumps old fluids, without ever checking levels first... and then fills both to proper levels. Even if they did notice the trans a couple ounces low, it would be no cause for concern and they certainly wouldn't look to see if it's in the trans....
Several dyno tuners have tuned bikes, and seen 10oz transferred during the tuning process. One posted that he tuned an '18 CVO Limited, and it transferred 10oz during the tune... so it seems it hasn't been fixed for the '18 models..
One, the clutch pushrod travels between the clutch cable/hydraulic actuator under the trans side cover to the the clutch in the primary, via this hollow shaft.
Two, the shaft is not sealed. It has a secondary job of allowing the pressure to equalize between the trans and primary, and vent out the trans vent, if necessary.
The only way you can lose 8oz of trans oil and have it show up in the primary, is via this shaft...... that much is agreed on. Now why/how it is doing this is an ongoing discussion...
The scary part of this issue is it is unknown how many bikes are affected. It is NOT an issue on all bikes. The transfer rate appears to be dependent on how hard you run the engine, higher rpms have been shown to increase transfer. If you don't look for it, most people won't know they have it...
For example; you ride easy between service visits. You may only have 2-3oz of transfer. The service tech dumps old fluids, without ever checking levels first... and then fills both to proper levels. Even if they did notice the trans a couple ounces low, it would be no cause for concern and they certainly wouldn't look to see if it's in the trans....
Several dyno tuners have tuned bikes, and seen 10oz transferred during the tuning process. One posted that he tuned an '18 CVO Limited, and it transferred 10oz during the tune... so it seems it hasn't been fixed for the '18 models..
Thank you Hat, This is the most concise and understandable explanation of the problem that I have seen so far. You explained what the problem is and $tonecold and Steve Cole, with the help of Max, have com up with the fix
Ultimate HDF Member
Joined: Jul 2014
Posts: 5,649
Likes: 430
From: MASS_hole
So, is the fix going to be sold to the MoCo so they can recall and take care of you guys. Or are you going to have to buy the oarts and oay the MoCo for the service? Or will warranty pay for the sevice and you only pay for the part?
Last edited by splattttttt; Jan 5, 2019 at 05:50 AM.
Stellar HDF Member
Joined: Mar 2013
Posts: 2,720
Likes: 1,835
From: In a house
Originally Posted by splattttttt
So.is the fix going to be sold to the MoCo so they they recall and take care of you guys.Or...
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mcgee10
Primary/Transmission/Driveline/Clutch
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Aug 7, 2019 01:12 PM
