Really do not believe RL has a product specifically formulated for common case wet clutch and manual non yellow metal ,non synchro manual transmission application, such as XL

granted that having Zn & Ph anti wear additives in motor oil used also for wet clutch and manual trans
is not required for the clutch & trans , but probably not detrimental.

hydrostatic power train tractors have a similar issue where one oil serves as both hydraulic and manual transmission gear oil.

 

Opinions vary....I believe Charley on here has over 100,000 miles on his Sportster using 75W90 synthetic gear oil with no issues. May not be good enough for you but it is for me. I have 11,000 and some change on mine using Red Line 75W90 GL5 with NO issues.

 

Have verified, 1 Decene HOMOpolymer hydrogenated compound, C10H20, contained in the H-D SYN3 MDS is indeed a poly alpha olefin(PAO) defined by API as group 4 synthetic lithium lubricant.
Believe this to be quite significant.
Minimum is 50%
So ,SYN3 could be 50% group 4, 20% group 2, 20% group 1 & 1O% additives.

Did find some chatter on BIT OF about Phillips 66, Spectrum, Red line.
Appears Spectrum is a speciality lubrication blender with several subsidiaries, making lawn mower, tractor, outboard engine lubricants, automotive is also included in the product mix.
Red line maybe one of them, but find it difficult to trace the corporate structure.
Hopefully, RL will not be greatly directed by the corporate structure and left along to do their thing as a speciality lubrication blender.

Appears RL furnishes a product package for H-D touring, dynamic, softails with the three separate oil cases, engine, primary, trans., all using a different oil.

The back label on SYN 3 formulated to use in both engine and wet clutch/trans and Formula + formulated for use in wet clutch/trans case, only , states
"formulated to maintain the coefficient of friction for proper clutch operation"
Too high a lubricity factor the clutch plates slip, too low a lubricity factor the clutch plates lock up.
Not all clutch plates manufactures use the same material.
Surely H-D, has extensively tested both lubricates for proper clutch operation and trans wear.

 

Good to know Syn-3 at least contains a polyalphaolefin as base, even though its in concentrations which are, I believe, lower than standard. Most PAO synthetics are comprised of something more in the order of 70% Polyalphaolefin base with 30% being either a Dino oil or Ester of some sort as PAO's don't absorb the constituent elements of additives packages very well on their own.

Though I'm cautiously impressed, the fact remains that lower concentrations of true synthetic in the can mean higher concentrations of VI improvers will be necessary to create "multigrade" formulations. It is these improvers, more than base oils, which shear and degrade, shortening an oil's service life. My "guess" is that this is why HD clearly discourages extended change intervals when using Syn-3.

The key point in all of this, IMHO, is for the most part price. Even though I use a GV synthetic myself, I can take no issue at all with guys who uphold that a good Dino and scheduled change intervals is all you'll ever need. They're certainly far more correct in their thinking than folks who pay $$ for a "synthetic", and don't really get one, then leave it in the engine to shear like **** for extended periods to justify the $$. I'm personally in the camp that chases diminishing returns, willing to pay increasing $$ for minor improvements,,, so long as I darn well get them,, and thats the point; knowing if you're getting what you pay for. Beyond that, your choice = your money = your business.

 

And according to the latest MSDS on Harley SYN 3 Citgo makes it for them.

Harley Davidson FORMULA+ Trans and Primary Chaincase VOA

(Mini VOA via Amsoil)

Petroleum based.

Ca 169
P 230
B 210
S - some
Zn - essentially none
No other elemental additives.

Vis. within SAE 50 range.

Listed as a GL-1, does test out as a GL-3.

Harley owners may be better served by using a lube that meets GL-4 requirements and has more P and Zn, and a basestock resistant to shear.

Here's the published specs:

Quote:


Harley Davidson Formula+
Application: recommended for heavy-duty service in manual transmissions where the manufacturer normally recommends either engine oils or GL-1 lubricants.
Specific Gravity: 0.857
Pounds per Gallon: 7.14
Viscosity, ASTM D 445,
cSt at 40°C: 168.04
cSt at 100°C: 20.10
Viscosity Index, ASTM D 2270: 139
Brookfield Viscosity, ASTM D 2983,
cP at -26°C - 28,800
cP at -40°C - n/m
Pour Point, ASTM D 97, °F (°C): -60 (-51)
Flash Point, ASTM D 92, °F (°C): 507 (264)

 

Do not believe shear down is an issue with SYN3 for use XL wet clutch/trans case because this case runs at much lower temperature
and the lubricate is subject to less shear than found in the hotter air cooled engine and oil shear from piston rings

 

Was talking about formula +, NOT SYN3

Oh and for the record, I have ran Harley SYN3 in my trans and RED Line 75W90 gear oil beats it hands down as to clutch hook up, finding neutral and smooth shifts. I will never go back. That's my personal experience.

 

Was addressing comment by HK on shear down in trans using SYN3.
Is S , typical additive for gear lubricate to absorb impact giving it the rotten egg smell, detrimental to wet clutch operation?
What lubrication specification is important to wet clutch operation and how is it measured.
JASCO MA spec maybe the key.
Do not believe viscosity is the metric for proper wet clutch operation.

Is the VOA available for RL 75W90? How much S?

 

JASO MA is a Japanese oil spec for motorcycles that have the same oil lubricating the engine, primary, transmission and clutch, HD makes no mention of the JASO spec in the fluid requirements.

S is sometimes used in Diff lubes as an Extreme Pressure additive.
It does not show up normally in UOA/VOA.

Many limited slip diffs use a clutch type lock up.

Since all of the gears in the current Harley Sportster transmission are helical cut except the two for 1st gear (straight cut), they do have some of the sliding characteristics of diff gears, not as extreme as the sliding in a diff.

http://www.amsoil.com/newsstand/auto...-oil/?zo=34396
"Most manual transmissions have helical gears that do not require GL-5 performance. The helical gear is almost a straight-cut gear, but on an angle. There is spiral action and very little sliding action, and there is less need for extreme pressure additives. GL-4 gear lubes provide less extreme-pressure additives than GL-5 lubes. In manual transmissions using helical gears, AMSOIL typically recommends either Synthetic Synchromesh Transmission Fluid (MTF) or Synthetic Manual Transmission and Transaxle Gear Lube (MTG)"

Red Line MT-90 is a GL4 lube.

http://machinerylubrication.com/Read...-modifiers-use
The purpose of a friction modifier varies based on the application. In a combustion engine, the goal is to lower the amount of friction, thereby gaining fuel economy. In clutches, automatic transmissions and industrial applications, the aim is not simply to control friction in order to maximize efficiency but to reduce slippage. To a degree, this seems a bit counterintuitive, since a lubricant’s objective is to reduce friction and wear. However, there are many situations in which a certain amount of traction friction is required for equipment to operate properly. The friction modifiers used in these applications are not intended to increase or decrease friction but to act differently under specific shear conditions. This essentially smooths the transition from a dynamic condition to a static condition, such as during a gear change in a transmission or the engagement of a clutch.

 

RL MT90 manual transmission gear oil might be a better selection that RL 75W90 differential oil for XL clutch/manual non SYN trans application.
The lubricity factor is less than the super slippery RL 75W90 differential lubricant.

RL states MT90 is recommended for GL-1, GL-3 & GL-4 applications.

Warren Oil blends a GL-1 spec oil available at Tractor Supply for use in vintage Ford 8N tractors for use in both manual non SYN trans
and hydraulic system to drive the three point implement lift on the rear of the tractor.
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