Harley Evo: Primary & Trans

[Gene K]

A friend recently inherited a Harley Evo. It came with engine oil which he is going to continue using for the engine (He thinks his dad was using engine oil in the engine, primary and trans). He has access to Mobil Delvac 1 Transmission Fluid 50 (MT-1 / GL-4) at work which is a 50 (Engine) or 90 (Gear) Grade MTL with viscosity of 17.5 cSt @ 100C and 146 VI. He was thinking of using it for primary and trans. Any thoughts?

Harley used to call for seperate products in all 3 applications but in recent years has consolidated to only one product for the primary and trans.

 

[MotoTribologist]

Customers from my previous gig liked to use a fairly similar product to that delvac in the primary(actually an 80 instead of a 90), but then a heavier 140 gear oil in the transmission. I never had an issue come back and I usually had positive feedback from that combination.

 

[alarmguy]

A friend recently inherited a Harley Evo. It came with engine oil which he is going to continue using for the engine (He thinks his dad was using engine oil in the engine, primary and trans). He has access to Mobil Delvac 1 Transmission Fluid 50 (MT-1 / GL-4) at work which is a 50 (Engine) or 90 (Gear) Grade MTL with viscosity of 17.5 cSt @ 100C and 146 VI. He was thinking of using it for primary and trans. Any thoughts?

Harley used to call for seperate products in all 3 applications but in recent years has consolidated to only one product for the primary and trans.

1. Harley used to market 2 products, one for the transmission and the primary and one for engine oil. Since then there are more options but you still have those two options.

Good question and one that I doubt you will ever get an educated answer on other than if you want to try it, it MAY do no harm. I would never use it in the primary though. Its an unknown if it would damage the clutch.

If he wants to do what is best for the bike in my opinion is just use the called for lubricant which is still Harley Davidson Transmission and Primary Lubricant. If not I think its a bit of a wild card but doubt it would hurt the transmission even if its not the purpose that Mobil states.

"The designation API MT-1 denotes lubricants intended for non-synchronized manual transmissions used in buses and heavy-duty trucks. Lubricants meeting the requirements of API MT-1 service provide protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5."
Source = https://www.mobil.com/en/lubricants...roducts/mobil-delvac-1-transmission-fluid-50/

Speculation says Harley is GL1 possibly up to GL3

 

[gman2304]

Many people use 20w50 in all three holes and get great results. In my 2 old evo Harley’s I used Harley formula + dino in the primary, Redline Shockproof in the transmissions and Valvoline Vr1 20w50 in the crank. Same combo with my 2 TC Harleys . Never a false neutral and shifts as smooth as a baby’s @$$!

 

[Gene K]

1. Harley used to market 2 products, one for the transmission and the primary and one for engine oil. Since then there are more options but you still have those two options.

Good question and one that I doubt you will ever get an educated answer on other than if you want to try it, it MAY do no harm. I would never use it in the primary though. Its an unknown if it would damage the clutch.

If he wants to do what is best for the bike in my opinion is just use the called for lubricant which is still Harley Davidson Transmission and Primary Lubricant. If not I think its a bit of a wild card but doubt it would hurt the transmission even if its not the purpose that Mobil states.

"The designation API MT-1 denotes lubricants intended for non-synchronized manual transmissions used in buses and heavy-duty trucks. Lubricants meeting the requirements of API MT-1 service provide protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5."
Source = https://www.mobil.com/en/lubricants...roducts/mobil-delvac-1-transmission-fluid-50/

Speculation says Harley is GL1 possibly up to GL3

Mobil Delvac 1 Is recommended for MT-1 and GL-1, GL-2, GL-3, GL-4 applications.

The original manual calls for different products in the primary and secondary as HD used to have two different fluids for that purpose. Everything I've ever heard though says the primary is not a demanding application. It's surprising how many guys just run 20W-50 MC Synthetic in all 3 applications (Which is what he suspects is currently in it).

 

[Gene K]

Many people use 20w50 in all three holes and get great results. In my 2 old evo Harley’s I used Harley formula + dino in the primary, Redline Shockproof in the transmissions and Valvoline Vr1 20w50 in the crank. Same combo with my 2 TC Harleys . Never a false neutral and shifts as smooth as a baby’s @$$!

He suspects it currently has 20W-50 MC Synthetic in all 3 locations. If the RL is GL-5 I have always attemted to avoid that unless the manufacturer specifically authorizes GL-5. However I suspect it's likely non-issue with the HD due to how common it is to run it without issue.

 

[repairman54]

Redline in the tranny of my '01 TC. Better shifts and positive neutrals. No HD ''fits all'' lubricants in my bike.
Had 2 primary tensioner plastic shoes come apart in mine, first one at 1k miles. 2nd one at 4k miles. Can't remember what's in there now but I think it's Redline but definitely not HD stuff since going through the tensioner pad failures.

 

[Gene K]

Redline in the tranny of my '01 TC. Better shifts and positive neutrals. No HD ''fits all'' lubricants in my bike.
Had 2 primary tensioner plastic shoes come apart in mine, first one at 1k miles. 2nd one at 4k miles. Can't remember what's in there now but I think it's Redline but definitely not HD stuff since going through the tensioner pad failures.

In most applications failure of plastic guides or pads is a symptom of Improper chain tension.

 

[repairman54]

In most applications failure of plastic guides or pads is a symptom of Improper chain tension.

Both shoes/pads were replaced by the dealer while still under warranty. Didn't get a look at them as it was a drop it off and *** failure.
No issues since then and tension was right on when I put the Redline in.

 

[blueglide88]

In my 1988 Evo I use Rotella T 15w-40 in the primary. I swap it out every oil change with the engine oil.
Keeps the stator magnets from attracting too much crud. It has worked for me never I have replaced a stator and you can see my mileage in my sig.
Trans uses 80w-90 gear lube in the trans, whatever is on sale. Change every other oil change. 6k
Engine uses 20w-50 VR1 or any MC oil. Change every 3k