Softail Models Standard, Custom, Night Train, Deuce, Springer, Heritage, Fatboy, Deluxe, Rocker and Cross Bones.
Sponsored by:
Sponsored by:

Fatboy fluids question

Thread Tools
 
Search this Thread
 
Old Feb 11, 2012 | 10:11 AM
  #1  
94-Sporty's Avatar
94-Sporty
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 64
Likes: 0
Default Fatboy fluids question

I use castrol 20W50 in the motor and HD primary/Tranny.
When my 1998 is on the jiffy stand, after a couple of days there will be maybe 2 or 3 small drops of oil on the ground. This only started a couple of months ago. I have noticed that the less lean on the bike, the lesser the drops., so I prop it up a little now. I suspect a shifter seal or something between the inner primary case and the tranny as it appears to be coming down the back of the inner primary.
I have checked the fluids and they appear fine, I change them every 3k miles so they are all in excellent condition, but this fluid is dark.
I cant determine which fluid it is....so finally here is my question. Can you recomend a transmission fluid that has a color like red? I am figuring if I put UV dye in the primary, red tranny and regular engine oil I should be able to have a better idea which fluid it is. I have a feeling I am going to be pulling off the primary in the next few months and replacing all the seals, but I still hate not knowing what the fluid is.

Thanks Guys.
 
Reply
Old Feb 12, 2012 | 08:02 AM
  #2  
94-Sporty's Avatar
94-Sporty
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 64
Likes: 0
Default

BTT for the weekend crew....
 
Reply
Old Feb 12, 2012 | 08:08 AM
  #3  
smitty901's Avatar
smitty901
Seasoned HDF Member
Veteran: Army
15 Year Member
Liked
Community Favorite
Joined: Feb 2008
Posts: 22,999
Likes: 11,439
Default

Dark color is most likely engine oil. Catch a drop in a cup if you can smell and taste can help you figure it out
 
Reply
Old Feb 12, 2012 | 08:12 AM
  #4  
Notgrownup's Avatar
Notgrownup
Seasoned HDF Member
15 Year Member
Loved
Top Answer: 1
Top Answer: 3
Joined: Mar 2009
Posts: 24,682
Likes: 9,166
From: Snow Hill, NC
Default

clean everything under there with brake cleaner and a rag....the cleaner the better...then put baby powder or talc powder on a clean rag...plenty of it...puff it around where you think the leak is coming from...this will help you pin point the source....
 
Reply
Old Feb 12, 2012 | 10:36 AM
  #5  
94-Sporty's Avatar
94-Sporty
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 64
Likes: 0
Default

Someone told me about the talc and I thought he was yanking my chain..will give it a try.

Whats getting me is the fluid looks like it is old, like oil that is way past its prime. Level in my oil tank is fine and it is much cleaner and more viscous.

should engine oil taste different to tranny fluid, what should it taste like :-)
 
Reply
Old Feb 12, 2012 | 11:01 AM
  #6  
RHillbilly's Avatar
RHillbilly
Road Warrior
Joined: Jan 2008
Posts: 1,446
Likes: 8
From: greenwood, mo
Default

Redline shockproof best tranny oil
 
Reply
Old Feb 12, 2012 | 04:05 PM
  #7  
Notgrownup's Avatar
Notgrownup
Seasoned HDF Member
15 Year Member
Loved
Top Answer: 1
Top Answer: 3
Joined: Mar 2009
Posts: 24,682
Likes: 9,166
From: Snow Hill, NC
Default

Find the source....have you done anything different lately...used a different cleaner, or cleaning procedure... maybe it was spilled on the top somewhere???
 
Reply
Old Feb 12, 2012 | 08:04 PM
  #8  
94-Sporty's Avatar
94-Sporty
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 64
Likes: 0
Default

it concerns me that it only happens when the bike is leaning on the jiffy. if i put a piece of wood under the jiffy, decreasing the lean i dont see any drops. The only thing different is that I dont use stock HD 20W50 any more, since I was out of work, the last 2 oil changes i used Castrol 20W50 from Walmart. Primary and tranny are from HD dealer, bought a few a whiel ago. Bike is behaving fine and when I check the fluids I cannot detect any loss.....
 
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 Feb 12, 2012 | 08:06 PM
  #9  
94-Sporty's Avatar
94-Sporty
Thread Starter
|
Advanced
Joined: Jun 2009
Posts: 64
Likes: 0
Default

thats why I was thinking get a red tranny fluid and I dont know.. maybe UV dye in the primary. then I can distinguish each of them.

does that make sense?
 
Reply
Old Feb 12, 2012 | 08:08 PM
  #10  
outgood's Avatar
outgood
Tourer
Joined: May 2011
Posts: 324
Likes: 8
From: Florida
Default

I wouldn't put castrol in my hd

Amsoil oil study II

If u don't wanna read the entire study, look at the last comparison chart on pg 24.
Amsoil is pricey, so I run Mobil 1 syn.
 

Last edited by outgood; Feb 12, 2012 at 08:19 PM.
Reply



All times are GMT -5. The time now is 10:57 AM.

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