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M8 6 speed transmission.

Started by Durwood, April 07, 2019, 08:58:25 AM

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Durwood

I had a customer with a 124" M8 build report that he busted 2nd gear and was curious if anyone here has had the same issue?

He said that he's heard of a half dozen with big engine builds that did the same thing but I haven't seen this anywhere myself.

kd

Not an M8 but my  2011 120 TC build striped 3rd gear bare and I have heard of others with the 3rd gear issue.   
KD

bigcraig

I have seen a few reports of this on a FB road glide owners group. Most of them lack a lot of details other than only stating that big bore builds were done.

Even after I tried to inquire about if they monitored the bikes for possible trans fluid migration, a know possible issue with some M8s. Those questions were never answered.

So, we are left wondering, if the added HP load is too much for the factory transmission, was/is there a heat treat issue with some transmission gears or could it simply be folks had a migration problem they failed to catch and/or monitor.

As they say, the world may never know!

PoorUB

Waiting for the guys that drag race to post! :pop:

Seems to me there are a few guys running big cubes and racing with stock transmissions that have little issues.
I am an adult?? When did that happen, and how do I make it stop?!

Durwood

Quote from: PoorUB on April 07, 2019, 09:34:41 AM
Waiting for the guys that drag race to post! :pop:

Seems to me there are a few guys running big cubes and racing with stock transmissions that have little issues.
That is where I am UB. I am by no means easy on my bike but I haven't had the 124 very long.

This guy's failure was a breakage and not from lack of lube.

Durwood

Quote from: kd on April 07, 2019, 09:23:20 AM
Not an M8 but my  2011 120 TC build striped 3rd gear bare and I have heard of others with the 3rd gear issue.
I have seen some 3rd gear failures with the TC 6spd. But this is the first I have heard of second gear failure in an M8.


No Cents

   Daren...I know exactly what bike you are talking about and I honestly think it was a case of missing a gear.  :wink:
Let's just say it showed all the signs of a missed gear...and then trying to cram it into gear.
But what do I know.   :nix:
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

festus

2017 M8  stage 4 
Now with a t man 226   
Dynod At 124 SQ  valley racing 
Tore up 2nd gear  locked up the tire lucky my
Brother in law and my sister on the back we're only doing
25 when it locked up   

Background  he broke two belts and when I rode it
The clutch came on almost immediately of the bar??
Was this an issue? Don't know
Harley replaced the whole gear set and primary under
Warranty   With what he was told the update 2018 version 

Nothing is impossible if you don't have to do it yourself.

harttoo

Mine is in for transmission repair now.Third gear had teeth missing.Stage 2 build.

crewchief25H

I've seen a 18 CVO with less than 300 miles back at my local dealer last spring with missing teeth on 3rd gear.

Billy

 2019 CVO Road Glide with Fuel Moto 128 kit. Maybe 200 miles after the install.

Third Gear

[attach=0,msg1291223]
Lazyness is the Mother of Invention

Ohio HD

Yikes, maybe Andrews should fire up their gear hobber again.

MakoHD

my fathers 120 busted 3rd gear but it had like 5oz in the transmission because it had fluid transfer
my uncles cvo busted 6th gear and all it has its a cam.
mine just makes an annoying shattering noise at idle, i believe its coming from that spring loaded 5th gear, i have grudge a box on order they state it'll get rid of the noise. the noise goes away when i pull in the clutch.     

kd

I'm hoping my new GrudgeBox will cure my 3rd gear experience.  :wink:
KD

No Cents

   I wonder if a lot of what we see is some guys choose to run a thinner motor oil in their tranny instead of a thicker gear oil that will cling to the gears keeping them lubed as they spin. Of course the transferring issue on the M8's could play a big role if the tranny was to get low enough with the thinner motor oil and it can't cut the mustard when it gets low and it doesn't bath the gears any longer and cushion the meshing action like the thicker gear oil would.  :nix:  Just thinking out loud here.
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

Billy

The trans pic I posted in reply 10 had formula plus in it and was full of fluid. Waiting on a GrudgeBox to go back in this one.

I believe axial forces from the helical gears combined with high torque loads from the 128 pushes the main and lay shafts slightly apart in the center (where third gear is) causing this type of damage.

Lazyness is the Mother of Invention

Geezer_Glider

I'd second that idea. Wonder if they thought that big Christmas tree gear set would help hold the shaft straight. Be interesting to hear what Baker or Andrews would say about the 6 speed.
Just saying,
R Meyer

MakoHD

Quote from: No Cents on April 08, 2019, 06:50:31 AM
   I wonder if a lot of what we see is some guys choose to run a thinner motor oil in their tranny instead of a thicker gear oil that will cling to the gears keeping them lubed as they spin. Of course the transferring issue on the M8's could play a big role if the tranny was to get low enough with the thinner motor oil and it can't cut the mustard when it gets low and it doesn't bath the gears any longer and cushion the meshing action like the thicker gear oil would.  :nix:  Just thinking out loud here.

I use in the transmission severe gear SAE 250 by AMSOIL SYNTHETIC EXTREME PRESSURE LUBRICANT... THICKER THEN HONEY.

cmashark

I'm thinking a DD7 is on my Christmas list.  I loved it in the bike Chad at Wide Open Cycles put together for me.
2021 FLHXSE

No Cents

   Bert Baker told Randy last week that a T/C 6 speed gear set won't cross over into a M8 without changing a lot of stuff. Bert said right now it's cheaper to replace an M8 broken gear set with factory parts.
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

MakoHD

Quote from: No Cents on April 08, 2019, 11:30:23 AM
   Bert Baker told Randy last week that a T/C 6 speed gear set won't cross over into a M8 without changing a lot of stuff. Bert said right now it's cheaper to replace an M8 broken gear set with factory parts.

Then why not just doing a grudge box you'll get better performance and with the over drive 6th you'll drop 250rpms when cruising onthe high way. I also got mine with neutral all the way up everything down, also the drum has the ignition kill when you want to shift with out letting go of the gas or using the clutch. I just don't see the purpose of 7 speed when the grudge box is available.

No Cents

  I don't own a M8.
It was a customers bike of Randy's in question from the OP.
08 FLHX my grocery getter, 124ci, wfolarry 110" heads, Burns pipe, 158/152 sae

Pirsch Fire Wagon

Yes, Second and Third Gear. Seen more Third than anything. About 6 Total. "They" know there's an issue.
Tom

rbabos

Quote from: PIRSCH FIRE WAGON on April 09, 2019, 04:00:24 AM
Yes, Second and Third Gear. Seen more Third than anything. About 6 Total. "They" know there's an issue.
Apparently so does Google. Do the problems ever end with this M8?
Ron

Admiral Akbar

All the gears in the m8 tranny are the same as later twincams except for the countershaft.  Wouldn't be surprised if it interchanges.  Mainshaft is the same. 2nd/3rd gear countershaft are the same.

jbroski

I can only comment about my bike, i'm running the stock trans with no issues. Ran it for 6400 miles before checking/changing fluid, went back with formula plus due to it working. Baker is a great company but grudge box is not for me

rbabos

Quote from: Admiral Akbar on April 09, 2019, 09:11:11 AM
All the gears in the m8 tranny are the same as later twincams except for the countershaft.  Wouldn't be surprised if it interchanges.  Mainshaft is the same. 2nd/3rd gear countershaft are the same.
So, basically some are reaching the design limit of the gear box then?
Ron

FSG


Freedom1974

Great more things to worry about !

joe_lyons

 I had a customer blow through 3rd gear on his 17. Built 114".
Powerhouse Cycle & Dyno - Performance is our passion 816-425-4901

08flstf

Well I think I just blew through my 3rd gear yesterday. Just got my 124 tuned the day before and took it out for my first test ride and apparently 3rd gear wasn't up to the task. Is there a more economic solution than going with the grudge box? I could do that if I have to but if there is another solution that might still be reliable I would like to explore other options. I always try to do all my own work when I can but have never gone into the transmission, nor do I have any of the specialty tools that may be required. Wondering if Baker or anyone else might make replacement gears or other parts that might be more robust vs replacing the whole gearset.

Billy

Quote from: 08flstf on April 29, 2019, 04:47:30 AM
Well I think I just blew through my 3rd gear yesterday. Just got my 124 tuned the day before and took it out for my first test ride and apparently 3rd gear wasn't up to the task. Is there a more economic solution than going with the grudge box? I could do that if I have to but if there is another solution that might still be reliable I would like to explore other options. I always try to do all my own work when I can but have never gone into the transmission, nor do I have any of the specialty tools that may be required. Wondering if Baker or anyone else might make replacement gears or other parts that might be more robust vs replacing the whole gearset.

I think your only options are to repair/replace yours with factory parts and expect the same durability, or the grudgebox. I've been waiting over a month for the grudgebox.
Lazyness is the Mother of Invention

jbroski

Quote from: Billy on April 29, 2019, 01:07:54 PM
Quote from: 08flstf on April 29, 2019, 04:47:30 AM
Well I think I just blew through my 3rd gear yesterday. Just got my 124 tuned the day before and took it out for my first test ride and apparently 3rd gear wasn't up to the task. Is there a more economic solution than going with the grudge box? I could do that if I have to but if there is another solution that might still be reliable I would like to explore other options. I always try to do all my own work when I can but have never gone into the transmission, nor do I have any of the specialty tools that may be required. Wondering if Baker or anyone else might make replacement gears or other parts that might be more robust vs replacing the whole gearset.

I think your only options are to repair/replace yours with factory parts and expect the same durability, or the grudgebox. I've been waiting over a month for the grudgebox.

not claiming this is the fix or anything like that. I bought an oem transmission and sent it to liberty gears and had them enhance it, cryo treat, shot peen, polish. I believe these are the correct terms. I have not used it yet because I can't seem to break the stock one. we are running an oem 5 speed with this done and very good results so far

08flstf

April 30, 2019, 07:57:31 AM #33 Last Edit: May 19, 2019, 09:27:26 AM by FSG
Quote from: jbroski on April 30, 2019, 06:14:26 AM
not claiming this is the fix or anything like that. I bought an oem transmission and sent it to liberty gears and had them enhance it, cryo treat, shot peen, polish. I believe these are the correct terms. I have not used it yet because I can't seem to break the stock one. we are running an oem 5 speed with this done and very good results so far

Ok I'm confused. I'm riding a 2018 FLTRU M8 with the stock 6 speed. What type of transmission are you referring to? Don't know if Jims has any options for the M8 6 speeds or if anyone else does besides Baker. What would be an approximate cost for the work you referenced by Liberty?

sfmichael

April 30, 2019, 08:10:57 AM #34 Last Edit: May 19, 2019, 09:29:59 AM by FSG
Quote from: 08flstf on April 30, 2019, 07:57:31 AM
Quote from: jbroski on April 30, 2019, 06:14:26 AM
not claiming this is the fix or anything like that. I bought an oem transmission and sent it to liberty gears and had them enhance it, cryo treat, shot peen, polish. I believe these are the correct terms. I have not used it yet because I can't seem to break the stock one. we are running an oem 5 speed with this done and very good results so far

Ok I'm confused. I'm riding a 2018 FLTRU M8 with the stock 6 speed. What type of transmission are you referring to? Don't know if Jims has any options for the M8 6 speeds or if anyone else does besides Baker. What would be an approximate cost for the work you referenced by Liberty?


"OEM 5 speed" is likely a 1999-2006 stock 5 speed from a Twin Cam
Colorado Springs, CO.

08flstf

Not trying to be smarta$$, but how does that relate to the M8 6 speed?

sfmichael

Quote from: 08flstf on April 30, 2019, 08:24:19 AM
Not trying to be smarta$$, but how does that relate to the M8 6 speed?

read the very first reply...  :smiled:

are you new here?
Colorado Springs, CO.

kd

Quote from: 08flstf on April 30, 2019, 08:24:19 AM
Not trying to be smarta$$, but how does that relate to the M8 6 speed?


I think jbroski is simply stating that at this point in time there are not a lot of options out there he knows of "or things to compare".  He is using the 5 speed he had modified as an example and is putting big power through as something that has worked for him and caused him to have his 6 speed doctored because of that.  He also states at this point he can not report on how well the application(s) worked on the 6 speed because it hasn't been put into service yet.  It will be interesting to see how well it does work though because jbroski has proven to be pounding on his big power bikes (racing) harder than most.
KD

jbroski

April 30, 2019, 08:51:59 AM #38 Last Edit: May 19, 2019, 09:31:15 AM by FSG
Quote from: 08flstf on April 30, 2019, 08:24:19 AM
Not trying to be smarta$$, but how does that relate to the M8 6 speed?

nothing, i'm an idiot. go buy a grudge box

08flstf

Ok when I said "not trying to be a smarta$$" that's actually what I meant. I misread the part that I highlighted myself. I thought he meant bone stock 5 speed, didn't realize he had had this work done to it. Sorry if I'm not catching on fast enough, just trying to find some options.

FSG

Quote from: Billy on April 29, 2019, 01:07:54 PM
Quote from: 08flstf on April 29, 2019, 04:47:30 AM
Well I think I just blew through my 3rd gear yesterday. Just got my 124 tuned the day before and took it out for my first test ride and apparently 3rd gear wasn't up to the task. Is there a more economic solution than going with the grudge box? I could do that if I have to but if there is another solution that might still be reliable I would like to explore other options. I always try to do all my own work when I can but have never gone into the transmission, nor do I have any of the specialty tools that may be required. Wondering if Baker or anyone else might make replacement gears or other parts that might be more robust vs replacing the whole gearset.

I think your only options are to repair/replace yours with factory parts and expect the same durability, or the grudgebox. I've been waiting over a month for the grudgebox.

not having had one apart I'm wondering if there's any realestate that can be stolen in there so as to fit a wider 3rd gear OR perhaps a different helical angle on 3rd so the gears are less likely to be driven sideways/apart 


Durwood

May 01, 2019, 04:52:57 AM #41 Last Edit: May 19, 2019, 09:34:32 AM by FSG
Quote from: 08flstf on April 30, 2019, 07:57:31 AM
Quote from: jbroski on April 30, 2019, 06:14:26 AM
not claiming this is the fix or anything like that. I bought an oem transmission and sent it to liberty gears and had them enhance it, cryo treat, shot peen, polish. I believe these are the correct terms. I have not used it yet because I can't seem to break the stock one. we are running an oem 5 speed with this done and very good results so far

Ok I'm confused. I'm riding a 2018 FLTRU M8 with the stock 6 speed. What type of transmission are you referring to? Don't know if Jims has any options for the M8 6 speeds or if anyone else does besides Baker. What would be an approximate cost for the work you referenced by Liberty?

The way I read it is they have a Twin Cam bike with the enhanced 5spd in that's hanging in there with the mods, and that he also had an M8 6spd modified but hasn't used it yet because he hasn't broken the stock one.


jbroski

broke 3rd gear last night, now to see what the enhanced stock M8 trans will take

NHBagger

Durwood, on one of the trike forums a guy with an 2018 lost 5th gear and they said 6th was ready to go.  Dealer said it was a defective part.

Deye76

Are these failures all touring bikes, or softails also?
East Tenn.<br /> 2020 Lowrider S Touring, 2014 CVO RK,  1992 FXRP

TMcGuire17

As I understand it the problem is with the hardening and the fact that third gear is cast into the main shaft. Its also my understanding that the grudge box isn't going to hold up for long either without back cut gears and possible retreating the 3rd gear and main shaft. My 128 blew third gear last night, has nothing to do with lubrication but everything with to much power for the stock set. I do have quite a few miles on it and trips down the strip but I don't think my warranty will cover it :-) :-( Right now Im inclined to replace with stock until there is a rock solid resolution to justify 3-5K$. Also a grudge box is going to take mnths to get!

festus

For those who have had the trans 2nd or 3rd gear go out.
Check your comp Sliding cam very closely.
The bike i posted about in reply#7 had a new tranny installed by Harley dealer. All new.
275 miles later sliding cam broke, riding in 6th gear and just rolled it back.
I cant post a picture? but I have one.
Nothing is impossible if you don't have to do it yourself.

harttoo

Got Mine back from the Dealer two weeks ago.Lasted 176 miles and first gear started to rattle.Back in the shop again.Wonder if I will get to use it this summer!

scotman623

Older thread, Just wanted to update I lost 3rd Gear today on my 19 CVO RG, first time out on my 128 big bore build...I was getting on the gas pretty hard but nothing crazy, went to grab 3rd and heard some strange rattling noise then nothing... All of the sudden my rear wheel locked up, thank god I stayed up and got off the side of the road...Bike back home now and I'm deciding what to do now, obvious the stock tranny doesn't like this kind of torque....
Always look forward...

Nastytls

April 07, 2020, 08:12:30 AM #49 Last Edit: April 07, 2020, 08:19:39 AM by Nastytls
This is all very interesting, considering that they just came out with a 131" that makes way more torque than the stock engines. Are there now going to be a flood of warranty claims for trannies exploding? You would think that they would have made sure the trans can withstand these large TQ #'s before releasing this new bigger engine.

Also, I believe jbroski is running race bikes with much higher power levels than what the average guy will be, so if these enhancements are working in one of his bikes, I'd say they are likely to be a good solution; especially if the Grudge Box are taking many months to acquire.

Pirsch Fire Wagon

Quote from: Durwood on April 07, 2019, 08:58:25 AM
I had a customer with a 124" M8 build report that he busted 2nd gear and was curious if anyone here has had the same issue?

He said that he's heard of a half dozen with big engine builds that did the same thing but I haven't seen this anywhere myself.

Third is the most predominate problem However, the MoCo did upgrade when replacing. Something about the Metallurgy of the originals. I'll see if I can find it in the Service Portal.
Tom

08flstf

I replaced my gearset with a brand new one and sent to Liberty's Gear and had them do their work to it. Only have a 1000 miles on it so not really a long term test, but so far so good.

Nastytls

Wasn't there flex found in the TC trap door on high HP/TQ builds? I think that's why Baker came out with a new door.

Maybe a similar setup would help this problem?

HD/Wrench

the M8 trans is the same as the TC only change is shift drum  2/3 common then still is . M8 makes more tq on avg then the TC did 

Fix the OEM box is less than after market and from what I have seen  first hand stronger .

JackGraves4619

R&D Motorsports out of Clearwater FL is making stock tranny's out perform Grudge Box. I talked to worker there a couple weeks ago. He told me turn around was about a week and they charge1400 to make you're stock transmission hold up to some Big Builds. He told me to drop off my transmission and I will not be disappointed. He also told me he was working on repairing 2 or 3 grudge box transmissions and that a Grudge Box sucks up about 10 HP over a stock transmission because of the mass of the unit. Hope this info helps someone. Contact Mark at R&D 727-447-4552

Don D

Contact Mike Beland at A1 Cycles in NC
561-603-6671

HogMike

2019 CVO limited with 35000 miles.

Lost 6th gear due to worn shift fork. Slider ring shows more than normal heat on one side. Little more wear than normal on the dogs for the main drive gear but no broken teeth anywhere.

We suspect lack of oil due to oil transfer in the first 5000 miles. I suppose damage was done at that time until last week when 6th gear would not engage totally.

Those that had the oil transfer issues on 2017-2019,20 touring bikes may want to check it.
:missed:
HOGMIKE
SoCal

hrdtail78

For the guys that have had trans problems with the HD 6 speed on the street.  Were you running a lock up?  Or the guys at the track that aren't using assisted shift.  Are you running a lock up?
Semper Fi

kd

July 30, 2021, 12:27:11 PM #58 Last Edit: July 30, 2021, 05:43:33 PM by kd
Nope.  A solid hit into 3rd from a well set Bandit Sportsman.  (X2  :crook: )
KD

FXDBI

Quote from: hrdtail78 on July 30, 2021, 11:47:35 AM
For the guys that have had trans problems with the HD 6 speed on the street.  Were you running a lock up?  Or the guys at the track that aren't using assisted shift.  Are you running a lock up?

Smoked the 3rd gear using SE spring and the extra plate clutch pack with my skinny 145lbs .  Bob