Author Topic: M8 trans fluid leaking in primary  (Read 121603 times)

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Offline HDDOC

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Re: M8 trans fluid leaking in primary
« Reply #1475 on: May 15, 2019, 06:11:38 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?
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Offline HOGMIKE

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Re: M8 trans fluid leaking in primary
« Reply #1476 on: May 15, 2019, 07:47:11 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?

Probably not. But why would you if itís not a problem?
 :nix:
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Offline HDDOC

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Re: M8 trans fluid leaking in primary
« Reply #1477 on: May 15, 2019, 08:16:52 AM »
Just incase   LOL
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Offline IronButt70

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Re: M8 trans fluid leaking in primary
« Reply #1478 on: May 15, 2019, 09:54:18 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?
I read somewhere on another forum about a triglide owner on a cross country trip grenading his tranny because of the migration issue. I would keep a close eye on it.
Rollin down lifes hiway never looking back cuz something might be gaining on me

Offline Reddog74usa

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Re: M8 trans fluid leaking in primary
« Reply #1479 on: May 15, 2019, 12:45:45 PM »
 :down: :down: :down: :angry:
RIDE IT LIKE YA STOLE IT

Offline HDDOC

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Re: M8 trans fluid leaking in primary
« Reply #1480 on: May 17, 2019, 03:54:29 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?
I read somewhere on another forum about a triglide owner on a cross country trip grenading his tranny because of the migration issue. I would keep a close eye on it.

I am aware of the problem and do check the trans oil offten,   Thanks
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Offline Hossamania

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Re: M8 trans fluid leaking in primary
« Reply #1481 on: May 17, 2019, 05:43:49 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?
I read somewhere on another forum about a triglide owner on a cross country trip grenading his tranny because of the migration issue. I would keep a close eye on it.

I am aware of the problem and do check the trans oil offten,   Thanks

It's ridiculous that you should have to do that.
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Offline IronButt70

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Re: M8 trans fluid leaking in primary
« Reply #1482 on: May 17, 2019, 05:54:35 AM »
I have no oil transfer on my 2019 Tri Glide I wonder if the dealer would install the vent kit with no problem with transfer.?
I read somewhere on another forum about a triglide owner on a cross country trip grenading his tranny because of the migration issue. I would keep a close eye on it.

I am aware of the problem and do check the trans oil offten,   Thanks

It's ridiculous that you should have to do that.
1000%  :agree:
Rollin down lifes hiway never looking back cuz something might be gaining on me

Offline HDDOC

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Re: M8 trans fluid leaking in primary
« Reply #1483 on: May 18, 2019, 07:00:17 AM »
I agree it is a pain but if it ever does transfer I know now there is a fix.   Thanks
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Offline Durwood

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Re: M8 trans fluid leaking in primary
« Reply #1484 on: May 18, 2019, 07:56:47 AM »
Have you thought about cutting a reverse spiral into the inner bushing surface to cause increased flow away from the primary?
KD, it does not need it, here is a drawing of how the centrifugal force pushes the fluid.



The arrows represent how the fluid moves. The fluids are pushed to the widest part of the tube.
I made this to test how the fluid acts inside the rotating shaft, its made out of half inch pvc and has a half inch cpvc bushing inside. It spins at 2000 rpm and sits at about 25-30 degrees to make sure the theory works.



I'm trying out different shape bushing inside the tube, they are about an inch long and about a half inch from the end.
I'm using water as a test fluid, pouring it into the top opening, the water will flow right through when the motor is turned off, as soon as you turn it on the water is flung out the top end and will not go past the bushing insert.
For anyone interested I used Steve's bushing in the main shaft along with his little slinger on the push rod and all migration has ended.
By now it would normally be down 4 oz, but upon inspection this morning I have lost zero in 1200 miles or so.

Offline bigcraig

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Re: M8 trans fluid leaking in primary
« Reply #1485 on: May 19, 2019, 09:29:28 PM »
Milled trans cover, fat rod and AIM has, so far, cured my transfer issue.

I will keep monitoring fluid levels, but I think I have this problem licked. I am also under a firm OPINION that just doing the mill work on the trans cover will cure the problem alone. I am however, to busy/lazy to do all the testing to prove my theory.


Offline metaliser

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Re: M8 trans fluid leaking in primary
« Reply #1486 on: May 21, 2019, 04:54:03 AM »
Milled trans cover, fat rod and AIM has, so far, cured my transfer issue.

I will keep monitoring fluid levels, but I think I have this problem licked. I am also under a firm OPINION that just doing the mill work on the trans cover will cure the problem alone. I am however, to busy/lazy to do all the testing to prove my theory.
That's a good job Craig but wouldn't drilling a few holes on that same side for a poor mans fix basically do the same ? Just Curious.

Offline bigcraig

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Re: M8 trans fluid leaking in primary
« Reply #1487 on: May 21, 2019, 11:19:03 AM »
Milled trans cover, fat rod and AIM has, so far, cured my transfer issue.

I will keep monitoring fluid levels, but I think I have this problem licked. I am also under a firm OPINION that just doing the mill work on the trans cover will cure the problem alone. I am however, to busy/lazy to do all the testing to prove my theory.
That's a good job Craig but wouldn't drilling a few holes on that same side for a poor mans fix basically do the same ? Just Curious.

Maybe, but I think removing as much material as possible is too beneficial. And drilling all those holes would be a pain unless you use a mill, but if you have access to a mill why not just create a much larger area for the trans fluid to go.

It is my opinion that the stock trans cover design, along with the transmission pushing fluid up into that dome cavity, high enough to be level with the push rod, and a small bit of primary vacuum is what causes the migration problem. I would bet a shiny new penny on it!

While it is terrible to say, I hope one of my local buddies finds he has this issue, and I will try and talk them into just letting me put a milled trans cover on it with none of the other known "possible" remedies.  (I have two more trans covers I am going to mill out, just to have around for friends.)

Offline hd06

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Re: M8 trans fluid leaking in primary
« Reply #1488 on: May 21, 2019, 03:01:35 PM »
  How come you don't just put a vent on the primary and be done with it.   :nix:

Online 98fxstc

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Re: M8 trans fluid leaking in primary
« Reply #1489 on: May 21, 2019, 11:45:28 PM »
  How come you don't just put a vent on the primary and be done with it.   :nix:

I would guess pretty much the same amount of work for each fix
I would take the invisible fix any day of the week
and no vent to worry about clogging or allowing dirt, water in.

Offline FSG

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Re: M8 trans fluid leaking in primary
« Reply #1490 on: May 22, 2019, 12:06:28 AM »
  How come you don't just put a vent on the primary and be done with it.   :nix:

if it were me I'd fix the problem at the source rather than Bandaid it elsewhere

Offline RedDog

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Re: M8 trans fluid leaking in primary
« Reply #1491 on: May 22, 2019, 03:40:04 AM »

if it were me I'd fix the problem at the source rather than Bandaid it elsewhere

What is the source of the problem that needs to be fixed?  How do we fix it? Is your M8 transferring?

Offline Hossamania

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Re: M8 trans fluid leaking in primary
« Reply #1492 on: May 22, 2019, 04:50:53 AM »

if it were me I'd fix the problem at the source rather than Bandaid it elsewhere

What is the source of the problem that needs to be fixed?  How do we fix it? Is your M8 transferring?

Start at the beginning of this thread. All explained in great detail.
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Offline bigcraig

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Re: M8 trans fluid leaking in primary
« Reply #1493 on: May 22, 2019, 12:14:30 PM »
  How come you don't just put a vent on the primary and be done with it.   :nix:

Honestly, I might later down the road if the issue raises it's head again.

Also, while my dealer is aware of my problem, they can't get me in until June 11th. I also specifically ask about getting the vent kit installed, hell I gave them the part number, but they are unclear if the moco will just send the vent kit for them to install, or if I have to go thru the whole "correct fluids, come back in 1k miles" nonsense. I took matters into my own hands. Frankly, after researching the problem and paying attention to what other folks have done, I personally feel I have it fixed.

Right now my only real concern is with the AIM s/c, as I just read on another forum of one failing, it is pushing dot4 past the piston seal. And, I know of one other person who returned their AIM for replacement, as the  advertised "wider friction zone" returned to stock characteristics. AIM replaced it, and the new one is working as it should, but the issue is being noted by other folks as well.

Offline hd06

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Re: M8 trans fluid leaking in primary
« Reply #1494 on: May 23, 2019, 02:18:33 AM »
  What part number is it.  Thanks for the reply

Offline FSG

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Re: M8 trans fluid leaking in primary
« Reply #1495 on: May 23, 2019, 03:02:13 AM »
INNER PRIMARY VENT SERVICE KIT    P/N  94100065


Offline hd06

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Re: M8 trans fluid leaking in primary
« Reply #1496 on: May 23, 2019, 12:08:30 PM »
 Harley should relieve these kits in in 2 or 3 weeks what i'm told. Harley Rep. drilled and taped my primary last september and put a vent hose and that fixed the problem that I had from the last 2 years on mine.

Offline FSG

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Re: M8 trans fluid leaking in primary
« Reply #1497 on: May 23, 2019, 01:40:32 PM »
to be found in the Section 


Online Karl H.

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Re: M8 trans fluid leaking in primary
« Reply #1498 on: May 24, 2019, 11:48:28 AM »
 :up:  :up: :up:
Dyna Wide Glide '03, Softail Deluxe '13, Street Glide '14, Sportster 883R '15

Offline harley_cruiser

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Re: M8 trans fluid leaking in primary
« Reply #1499 on: May 25, 2019, 03:23:45 PM »
Harley could fix this problem on new bikes very easily by machining a taper in the main shaft end on the transmission side or just machine a counter sink about an inch in the tunnel creating a step in the tunnel. Centrifugal force will keep the oil from climbing that step and it would act as a dam regardless of if it is drawn in by a vacuum or just splashed in on the clutch push rod. Once oil gets inside the tunnel there is nothing to stop it and centrifugal force pushes it into the primary.
They should also mill a grove in the push rod just at the edge of the tunnel. This would act as a slinger keep oil from entering the tunnel via the push rod.