ATF In The H-D Primary

[Propflux01]

I know many Harley riders debate over what fluids to use in the Primary. Newer H-D recommendations call for it's SYN3 motor oil. Some use it, others use formula +, others use ATF. My question is, whats the advantage/disadvantage of each in terms of lubricity, additives, compatability, etc. I am not looking for "my clutch feels better" or The manufacturer recommends it so I use it", but rather facts based on each ones material makeup.

 

[dnewton3]

This has been covered many times before. I don't know that you're going to find any conclusive data. You can do your research, but ultimately, you're going off the HD reservation, and will likely get flamed by some and praised by others.

OTOH - there are many guys over at DP that dump out the ATF from their transfer case (a link-plate chain-driven power transfer unit similar to your primary case) and put in 5w-30 motor oil, because some supposed "expert" wrote an article in a trade magazine (which was about as half-baked and thoughtless as any "article" I'd ever read).

Ironic, isn't it, that they seek what you are leaving, and you seek what they are leaving?

**************

Want a healthy and happy primary? Here's what you do:
1) keep the lube at the appropriate level. The NUMBER ONE cause of mechanical lube-related failure in any piece of equipment is over or under filling. Too much or too little oil/grease will kill equipment faster than anything else. Period.
2) choose a lube that meets the OEM specs (does not need to be OEM brand; just meet the specs or be close enough to not make significant difference)
3) follow the OEM maintenance plan, or use upgraded fluids for extended OCIs.

That is all that is required. No need to seek out the "perfect" fluid, because it does not exist. What you think is "better" is probably what someone else despises ...

 

[Silk]

Only 11% of members here have a Harley....

 

[Propflux01]

Originally Posted By: dnewton3
This has been covered many times before. I don't know that you're going to find any conclusive data. You can do your research, but ultimately, you're going off the HD reservation, and will likely get flamed by some and praised by others.


Perhaps, but All I have ever seen is people saying "Yea, it shifts so much better" or "HD recommends it so why not use their fluids". On another forum I voiced my opinion on ATF use in a primary, and the thread was closed because I could not offer "proof" that ATF was better or worse than SYN3 or "Primary Fluid". I was just trying to figure if anyone knew exactly what primary fluid IS, whats it made of (Haven't been able to find a conclusive answer), and why it would be OK to use a motor oil in a primary, but not ATF, when in fact they are really similar sans weight differences, as in they both are mineral based oils. Some of the responses i get are:
ATF shifts better ( which, btw, I do agree with)
ATF is not OEM recommended so it wont work or live
ATF doesn't 'climb' on the chain (does 20w-50 non-ester oil climb?)and therefore doesn't lube but only half.
ATF isn't safe for the stator
ATF lives in trannies that have electronic solenoids so it Is safe for stators
Formula + isn't the golden fluid anymore now it's SYN3 (or equivalent)
Formula + is the only fluid that should go in a primary
Formula + has additives that only a primary requires
Motor Oil is safe for the stator
Motor oil is what the manual calls for only.
Motor Oil doesn't climb on he chain to lube, just like what you see on that lucas Oil stabiliser display (you know, the one with the plastic gears)

These are some of the arguments for the various fluids. I am just trying to figure out the differences in these fluids and why some should only be used, why others cannot be used, and why some used to be OK and now they are not, etc.
Motor oil lubes the chain better

 

[boraticus]

Have you tried to contact HD to get their opinion? You'll probably get the "party line" but possibly they'll explain why they recommend the lubricants they do.

You might also contact an oil company that produces both the recommended oil and ATF to get their perspective on each lubricant.

Why not dump in some ATF, run if for a few years and post your results?

 

[BigCahuna]

I agree with using what the mfgr recommends. Except for using their branded oils. It states in the Harley service manual to use their oil or the equivalent. Their oil does not have an API spec on their bottle. And as I understand it there is no API spec for American motorcycle oils.Their manual also says in a blurb that's buried in the manual to use a SG rated oil, or a diesel oil if oil is needed and Harley's oil isn't available.Now as far as the primary oil is concerned, it's just requires the oil to cool and lube the clutch pack and provide lube to the chain.Harley's oil has been tested to be a 50 wt oil with a minimal additive package.Not alot of cleaning is required in that area.So if automatic trans fluid meets that requirement,which I can't believe it does some use it just because it's cheap. I personally feel better using a lube that more closely matches what the mfgr says to use.,,

 

[Propflux01]

Originally Posted By: boraticus
Have you tried to contact HD to get their opinion? You'll probably get the "party line" but possibly they'll explain why they recommend the lubricants they do.

You might also contact an oil company that produces both the recommended oil and ATF to get their perspective on each lubricant.

Why not dump in some ATF, run if for a few years and post your results?
thats just it, HD recommends SYN3 in all 3 holes, yet they still sell Formula+. I hjave spoken with several HD mechanics, and some swear Syn3 in all 3 holes, some say only in engine, F+ for primary, and 75w-90 in gearbox, yet others say they don't recommend Syn3 at all. so I get several different responses, hence the confusion.

 

[dnewton3]

Perhaps what you're not latching onto is that the anecdotal evidence suggests that lubricant choice is not as important as many would have you believe, for this particular application.

That was my point in mentioning the transfer case in GM trucks. The OEM spec is ATF. Some eschew this and use 5w-30. In all the circumstances, the only known failures have been in t-cases that were not properly maintained (the fluid level was not kept up). Which went right to my next point; the MOST important thing is proper lubricant level. Then fluids that are spec'd at or near the OEM fluid choice. Then a proper maintenance plan. Note: I am always an advocate of using OEM spec'd (not OEM branded) fluids.

How many failed HD primary cases have most of us seen? Probably very few. How many of these were because of the "wrong" fluid used? Probably a small fraction of the nearly non-existent failures. But how many use "alternative" fluids? Most likely a portion much greater than the fluid-caused failures.

There are times when the large preponderance of evidence (from those that venture over the fence to greener pastures) simply implies that the choice may not make a darn bit if difference.

 

[kballowe]

The HD-recommmended Formula+ is (roughly) a 50 grade fluid.
Most ATF is 20 grade.

The majority of the aftermarket clutch manufacturers recommend ATF. You get better clutch separation and spin-down with a 20 .vs a 50 and better "hook-up".

But hey - there's a a couple double-row gears and a double-row chain in there. It's not a candidate for high-tech lubrication.

Use what you want. Use what makes if shift better. Use what is easy on your wallet. Whatever. Seriously - it's hard to go wrong here.

Me? I use whatever I happen to have in the "leftover" bucket. It's typically a mix of partial quarts of SAE 30 and 15W-40 motor oils. Been doing this for going on 35 years.

 

[FLHRGator]

Originally Posted By: Tim H.
Originally Posted By: boraticus
Have you tried to contact HD to get their opinion? You'll probably get the "party line" but possibly they'll explain why they recommend the lubricants they do.

You might also contact an oil company that produces both the recommended oil and ATF to get their perspective on each lubricant.

Why not dump in some ATF, run if for a few years and post your results?
thats just it, HD recommends SYN3 in all 3 holes, yet they still sell Formula+. I hjave spoken with several HD mechanics, and some swear Syn3 in all 3 holes, some say only in engine, F+ for primary, and 75w-90 in gearbox, yet others say they don't recommend Syn3 at all. so I get several different responses, hence the confusion.


The owner's manual and service manual for my '09 both specifically call out Formula+ in primary and tranny. Maybe they changed that in '10, but somehow I doubt it. People seem to base their choice of primary and tranny fluid on getting rid of the first gear clunk and 5th gear whine. I don't really get that since the design of the tranny is what causes those sounds. I'd be more worried if they stopped. I've run Amsoil, Mobil 1, and now back to F+ in there and they still clunked and whined...just like they should.

 

[Zedhed]

Originally Posted By: FLHRGator
People seem to base their choice of primary and tranny fluid on getting rid of the first gear clunk and 5th gear whine. I don't really get that since the design of the tranny is what causes those sounds. I'd be more worried if they stopped. I've run Amsoil, Mobil 1, and now back to F+ in there and they still clunked and whined...just like they should.


A cacophony of sound, undampened by esoteric oils.....

 

[seldont]

I have an 06 Electraglide...I just use Rotella 15w40 or something similar that is wet clutch rated. 75w90 Mobil One in the gearbox and everything is happy! Most everyone I know who does their own Harley maintenance is using something similar, except the sportster guys whose primary and gearbox share the same fluid.

 

[EagleFTE]

What kballowe said on all counts. The MoCo walked away from the Syn-3, 3 in 1, idea a few years back. Some dealers are still pushing it (could be the $$$). But I’ve used left over oils, the old HD Chaincase oil, Formula+, HDEOs, all the same performance. Never used ATF but many do and like it and it is the preferred lube for many aftermarket clutches. The 5th gear whine is inherent to the newer tranny. I wouldn’t worry about it. Some try to mask it with fluid. The only problem I hear or see is from the people that just dump in xx amount and walk away not checking the level. The shop manuals are very specific on where the fluid should be on the clutch plates with bike level (can vary depending on year and model). Overfill and N will be hard to find. This is a very simple application. HDEO like Rotella is hard to beat price wise and what I've been using for a couple of years. But Formula+ is good too if you want to stay with OEM.

 

[BigCahuna]

Harley still recommends syn 3 for all three holes. Just checked their web site. And still has it on the bottle.And the screaming eagle model bike come from the factory with it.,,

 

[EagleFTE]

Yes SYN3 can be used in the Primary as can just about anything. According to the parts catalog “SYN3 can be used in the engine, primary chaincase, and transmission.” Also according to the parts catalog addressing Formula + Transmission and Primary Chaincase Lubricant it is “Formualted to maintain the coefficient of friction for proper clutch operation and provide adequate lubrication of the primary chain.” The reaction to SYN3 around 2002 by people who have been maintaining HDs for many years was:

a: I’m not putting motor oil in my tranny, too many superior gear lubes.

b: I’m not putting $11.50 anything in my primary. Why do that.

And Formula + was born, after several years anyway. The old semi-syn gear lube and separate chaincase products were actually pretty good and at a fraction of the price of SYN3. A lot of people just walked away and used none of the above after the SYN3 deal.

 

[BigCahuna]

I asked at my dealership ,which oil do you sell more of and it surprised me when he said syn3. I would have bet he'd say the HD360. I guess it the ease of getting it. You stop buy to look at stuff, and it's right there. May be overpriced,but alot of people worry that if they use something else it might void their warranty.I've tried it in two bikes and both bikes consumed it. Switched to Amsoil and Mobil 1 v-twin, and the oil usage went to almost nothing.Couldn't tell any difference in the primary tho.,,

 

[EagleFTE]

They do sell a lot of it. Not bad oil and UOAs look good. Just a bit pricey for what it is. I think you're right that a lot of people that bought HDs in the last eight years or so just use it because they don't have to second guess. But at that price you could use just about anything on the market. Still cheaper than a lot of OEM labled oils though. Some by a long shot.

 

[Propflux01]

Thanx for the opinions, guys! I wonder if guys (like me) that are using ATF are getting the results they are due to the weight of the ATF, or is it something in the ATF that's just 'better' than other fluids. If so, I wonder how a 10w-30 HDEO would fare?

 

[FLHRGator]

I would just go with 10W30 PCMO. All you need is a coolant and a lube. The primary doesn't have to contend with fuel dilution or combustion by-products. If you're worried about shearing put in something like Castrol GTX 10W40 and let it shear to 10W30.

 

[RedCellRacing]

Just to chime in since I am trying to decide what to start using on my 2009 sportster... I would agree that the primary has very basic lubrication needs but the XL's share the fluid between the primary and the trans. I have seen lots of folks that run 75w90 gear oil in the application but I am wondering what if anything the GL-5 lubes do to the sportster's trans (I would never put a GL-5 in an automotive manual trans). For the first change I am likely going to just dump AMSOIL MCV into it but if there are no concerns with using a GL-5 related to the trans or the result of friction modifiers on the clutch I may switch over to use up an overstock of the AMSOIL Severe Gear 75w-90 that I have.