15w-50 synthetic in H-D Transmission?

[troop]

Thoughts about using a 15w-50 synthetic oil in a 2009 6 speed transmission? Kinda like a jungle with scattered info. Some say GL-5 rated oils (75w-90/140)are not neccessary and maybe too much. Amsoil is the only company I see that rates their 20w-50 m/c oil as GL-1. Mobile says the 20w-50 m/c M1 syn is better than their 75w-90 gear lube, as does Amsoil. Lastly, the viscosity chart would show a 15w-50 oil actually closer in spec to a 75w-90 gear oil than a 20w-50 oil. Reason is I can get a qt of M1 15w-50 for $5 from a buddy. Heck, I'm sure it would be just fine but just throwing out for opinions...

 

[DrDusty86]

What kind of HD transmission, dodge- NV 4500,5600, G56, ford zf 5, zf 6?
Dusty

 

[troop]

Harley-Davidson 2009 6 speed

 

[oggb]

I'd find an oil that met JASO MA and use that.

 

[rn2fine]

Not sure if the JASO rating is going to be relevant as the oil is not going into the motor or the primary (clutch). I live in AZ where ambient air temps run up to 120 and even higher when running across the asphalt therefore I am running Redline Shockproof Heavy which is probably overkill. I would stick with gear oil myself as it appears more suitable for such an application than motor oil. Just my two cents worth. Have a good weekend.

 

[DrDusty86]

Shoot, I thought that was "heavy duty truck trans. I'm sorry, you are out of my area on motor cycles.
Getting old is starting to get old lol
Dusty

 

[kasedian]

 

[troop]

Originally Posted By: kasedian

Strange thing, even Amsoil recommends their 20w-50 MCV motorcycle oil over their gear oil for use in the transmission. Why's that?
http://www.teamrip.com/viscosity_chart.html

 

[Propflux01]

Originally Posted By: troop

Strange thing, even Amsoil recommends their 20w-50 MCV motorcycle oil over their gear oil for use in the transmission. Why's that?


Never question the Amsoil Gods!!

 

[troop]

Got my answer:
https://www.mobiloil.com/USA-English/Mot...-Davidsons.aspx

 

[BigCahuna]

It looks like Mobil says its OK for the primary, but doesn't say to use it in a transmission. But then again there are metric bikes where someone is using it in a shares sump configuration.,,

 

[car54]

The first 19k on my sv650 were on 15w-50. I'm at 22k now (switched to schaeffers 9000 5w-50), still on the original clutch with no slipping.

 

[troop]

True.. And most liquid cooled metric cruisers use 10w-40 oil in shared motor/transmission use. But they recommend 4-7k oil changes where as H-D says 20k on transmission. I'll use the 15w-50 syn in my motor and use some Amsoil 20w-50 in the tranny now that I have one quart of each on hand. Thanks ....

 

[KW]

Heck if you put Amsoil 20W50 in both you would not have to keep two oils on hand for the bike.

 

[msparks]

Many folks are complaining about gear whine in the newer 6 speeds. Running a heavier lube quiets it down.

AMSOIL recommends the 75w110 for the trans as an alternate. Likewise the 75w140 also works good. I used to use the 75w140 in the trans of my 99 BMW Twin because the shifting was so clunky. It did help a lot.

 

[Propflux01]

You have to consider more than just viscosity comparisons between a gear oil and a motor oil. IMHO , drain that M1 and either use shockproof or golden spectro 6-speed oil.