2014-2024 Touring Models This Section Is For Rushmore and Gen 1 M8 Touring models from 2014 to 2024
Sponsored by:
Sponsored by:

Twin Cam transmission vent tube

Thread Tools
 
Search this Thread
 
Old Aug 31, 2025 | 02:58 PM
  #1  
Ultra103's Avatar
Ultra103
Thread Starter
|
Road Warrior
15 Year Member
Liked
Loved
Community Favorite
Joined: Apr 2008
Posts: 1,940
Likes: 1,338
From: Arkansas
Default Twin Cam transmission vent tube

These keep breaking off. It's not that big of a deal to pull the cover and install a new tube and gasket (fiddly because some of the socket cap screws are hard to get to) but good grief, they only last a year or two with my usage as a primary vehicle.




Anyone found one that's better than the MoCo offering? GM used an all metal vent on some of their transmissions that had a cap loosely crimped on. I'm wondering if I can grommet one of those in there since the trans cover hole points about 45° upward.



 
Reply
Old Aug 31, 2025 | 03:33 PM
  #2  
Mongo1958's Avatar
Mongo1958
Stellar HDF Member
Photogenic
Liked
Loved
Community Favorite
Joined: Aug 2011
Posts: 2,761
Likes: 1,801
From: Newnan, GA
Default

Originally Posted by Ultra103
These keep breaking off. It's not that big of a deal to pull the cover and install a new tube and gasket (fiddly because some of the socket cap screws are hard to get to) but good grief, they only last a year or two with my usage as a primary vehicle.


Anyone found one that's better than the MoCo offering? GM used an all metal vent on some of their transmissions that had a cap loosely crimped on. I'm wondering if I can grommet one of those in there since the trans cover hole points about 45° upward.

I wish I could answer your question. The vent on my bike has been there since 2009 without any issues.
You watch, now that I said that, watch it break off, LOL!
 
Reply
Old Sep 1, 2025 | 09:40 AM
  #3  
timbo141's Avatar
timbo141
Road Warrior
15 Year Member
Liked
Loved
Community Favorite
Joined: Mar 2010
Posts: 1,421
Likes: 277
From: USA
Default

I have to be honest with you, I never heard of this problem with the vent tube... never.
Doesn't mean there isn't an issue, just never heard about it.
Obviously in your case something is amiss.
​​​​I have had two Road Glides in 18 years without a problem.
Maybe it's your transmission cover issue?
 
Reply
Old Sep 7, 2025 | 08:58 AM
  #4  
Ultra103's Avatar
Ultra103
Thread Starter
|
Road Warrior
15 Year Member
Liked
Loved
Community Favorite
Joined: Apr 2008
Posts: 1,940
Likes: 1,338
From: Arkansas
Default

IDK, they dry rot and fall apart. I'm going to make a copper vent and grommet it in this time.
 
Reply
Old Sep 7, 2025 | 10:20 AM
  #5  
propflux01's Avatar
propflux01
Road Warrior
Veteran: Air Force
15 Year Member
Liked
Community Favorite
Joined: May 2007
Posts: 1,433
Likes: 383
From: Arkansastan
Default

what are you washing the bike with? Maybe something is drying these out prematurely? I've never heard of this issue either. Strange one for sure!
 
Reply
Old Sep 7, 2025 | 10:45 AM
  #6  
nibroc's Avatar
nibroc
Road Warrior
15 Year Member
Liked
Loved
Community Favorite
Joined: Dec 2007
Posts: 1,610
Likes: 241
From: the 'ville' kentucky
Default

yes strange one for sure
 
Reply
Old Sep 7, 2025 | 12:40 PM
  #7  
Ultra103's Avatar
Ultra103
Thread Starter
|
Road Warrior
15 Year Member
Liked
Loved
Community Favorite
Joined: Apr 2008
Posts: 1,940
Likes: 1,338
From: Arkansas
Default

Originally Posted by propflux01
what are you washing the bike with? Maybe something is drying these out prematurely? I've never heard of this issue either. Strange one for sure!
It gets washed maybe 3 times a year with Meguiars soap and water - only by hand (I just wipe it down with detail spray otherwise). It gets rained on and left in the hot sun very regularly at work, lives in an air conditioned garage the rest of the time. I've used various transmission oils over the years, so that shouldn't be a factor.
 
Reply
Old Sep 7, 2025 | 02:13 PM
  #8  
MURPHCC1's Avatar
MURPHCC1
Club Member
Joined: Apr 2013
Posts: 5,801
Likes: 3,800
From: Cape Cod
Default

Still original vent tube on my 07......
 
Reply
HD Forum Stories

The Best of Harley-Davidson for Lifelong Riders

story-0

7 Surprising Harley-Davidson Products that Are Not Motorcycles

 Verdad Gallardo
story-1

8 Best Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-2

10 Worst Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-3

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

 Verdad Gallardo
story-4

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

 Verdad Gallardo
story-5

Harley-Davidson Reveals Super Cool Cafe Racer Concept

 Verdad Gallardo
story-6

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

 Verdad Gallardo
story-7

10 Motorcycles You Should Never Buy

 Joe Kucinski
story-8

10 Things Harley-Davidson Needs to Fix in 2026

 Verdad Gallardo
story-9

Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

 Verdad Gallardo
Old Sep 7, 2025 | 05:42 PM
  #9  
hattitude's Avatar
hattitude
Seasoned HDF Member
15 Year Member
Community Builder
Community Favorite
Top Answer: 10
Joined: Sep 2008
Posts: 14,113
Likes: 11,157
From: San Diego, CA
Default

Totally anecdotal, but........

I have '01, '03, '09, and '16 Twin cam bikes. I parked the '03 outside for 4 years, here in SoCal. I bought the '01 used in '17, but it lived the first 15 years of it's life in New Mexico under unknown storage conditions.

I have the OEM trans vent tube on all those bikes.

I also have 6 other close friends with Twin Cams with OEM trans vent tubes.

This is the first time I have heard of someone with this issue....


Now, I'll never be able to detail one of my bikes again, without looking closely at the trans vent...
 
Reply
Old Sep 8, 2025 | 11:52 AM
  #10  
MotoJockey's Avatar
MotoJockey
Grand HDF Member
Veteran: Navy
Joined: Jun 2017
Posts: 4,652
Likes: 3,960
From: Near Yosemite
Default

Originally Posted by hattitude
Now, I'll never be able to detail one of my bikes again, without looking closely at the trans vent...
Be sure to report back with your findings sir........
 
Reply



All times are GMT -5. The time now is 05:59 PM.

story-0
7 Surprising Harley-Davidson Products that Are Not Motorcycles

Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.

By Verdad Gallardo | 2026-04-29 16:50:35


VIEW MORE
story-1
8 Best Harley-Davidson Motorcycles Ever

Slideshow: Not every Harley gets it right, but these are the ones that genuinely earned their reputation.

By Pouria Savadkouei | 2026-04-15 14:23:21


VIEW MORE
story-2
10 Worst Harley-Davidson Motorcycles Ever

Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.

By Pouria Savadkouei | 2026-04-01 20:01:09


VIEW MORE
story-3
Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Slideshow: Killer Custom's "Jail Breaker" build focuses more on stance and visual aggression than mechanical overhaul.

By Verdad Gallardo | 2026-03-18 19:20:32


VIEW MORE
story-4
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.

By Verdad Gallardo | 2026-03-07 16:15:30


VIEW MORE
story-5
Harley-Davidson Reveals Super Cool Cafe Racer Concept

Slideshow: Harley-Davidson's new RMCR concept revives the café racer formula with modern hardware-and it may be exactly the reset the company needs.

By Verdad Gallardo | 2026-03-04 12:23:37


VIEW MORE
story-6
Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.

By Verdad Gallardo | 2026-02-24 18:19:44


VIEW MORE
story-7
10 Motorcycles You Should Never Buy

Slideshow: There is no shortage of great motorcycles to buy, but we would avoid these ten.

By Joe Kucinski | 2026-02-19 14:50:51


VIEW MORE
story-8
10 Things Harley-Davidson Needs to Fix in 2026

Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.

By Verdad Gallardo | 2026-01-13 18:33:17


VIEW MORE
story-9
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider

Slideshow: Graeme Billington's left-hand-drive Shovelhead is as much about problem-solving as it is about classic Harley form.

By Verdad Gallardo | 2025-12-30 11:27:08


VIEW MORE