As I remember, the W means the oil viscosity is measured at a low temperture, and non W is measured at a much higher temp. Can't remember the exact temps difference. Therefore oil such as 20W-50 means it flows at a certain viscosity at a certain temp (32Degrees?) giving it the 20 designation, and at I think 200 degrees behaves like a 50 Weight. I think 0,10,20 weight is measured at the low temp, and 30 weight and above is measured at the higher temps. Thus you couldn't have a 0w-20 weight oil if memory serves me correctly.

Okay, let the replies begin...

 

Just go to the dealer and ask what's best for your bike and then go with that from then on. That's what I did.

 

you have to know that you're begging to be flamed for a statement like that. [sm=bangbang.gif]

this may have worked for you, you may have an honest/knowledgable dealer. Q: what oil did your dealer recommend? Real dang good chance it was HD oil.

However,you'll notice in thissting andother oil strings inthis and otherforumsthe occasional comment about dealers threatening to void warranties if "non harley" oil is used. Some dealers may not sell anything other than the HD brands, possibly due to pressure from corporate.

The point being that the dealer may not have your best interest in mind when making the recommendations, it may be his best interests.

 

Amsoil all the way in my ride. Use their synthetic gear lube in the trans. As for cold weather the synthetics do notthicken due to the fact they have noparafins(wax)such as petrolium based lubricants do.

 

Folks,
As a Maintenance Planner in a Borax mine/refinery in the middle of the Mojave desert, I work with Tribologists, and Reliability Engineers to keep industrial machinery working 24/07 in a harsh environment. This includes gearboxes (also known as reducers, or gear reduction drives). When making the comparison between engine and transmission service...there are a few differences you need to consider:
[ol][*]Viscosity- The ability to flow (or pump) properly for a given temperature range is much more important in an engine (Where the oil pump has to circulate the oil) than it is in a transmission (where the gears are sitting in an oil bath). Also, the ability to remain thin at startup (where lubrication needs to get moving ASAP) and thicken the viscosity (to carry away more heat) is a much bigger issue inthe engine (Where temperatures rise much higher) than in a transmission. This is not to say it doesn't matter in a transmission...only that it matters for different reasons. In the "old days" (before additive packages) higher viscosity lubrication was recommended in transmissions for the sole reason of better adhesion to gear teeth, and thus being carried up out of the oil bath (and providing a higher degree of filming) and remaining between sliding gear teeth to reduce wear. However, it should be considered that you also have bearing surfaces in a transmission (where again...there is no pump to cause a positive force to flow onto surfaces) where thicker viscosity oils have a reduced ability to seep (the only method of close tolerance lubrication in an oil bath system).[*]Additive Packages- The additives greatly affect many properties of an oil. From the Viscosity Index rating (The sensitivity of the oil to to increase/decrease viscosity in response to operating temperature) to shear resistance (as properly mentioned by the original poster) and extreme pressure (ability to reduce the molecule chains from being "squished" apart)...all are effected by the additive package. In my opinion (and obviously the engineers at harley) the characteristics of a quality synthetic additive package give it the ability to perform in well 2 very different environments (An engine and a transmission).[/ol]

To anyone who I haven't bored to tears (and thus are still with me) I'll offer my 2 cents, and a couple of suggestions:
My 2 cents- I use mobil1 for v-twins...but I don't think there is a such animal as a "bad"
synthetic. It is important (no matter if you use synthetic, or mineral oils) not to
switch brands if you can help it (any lube is better than no lube in a pinch).
Sometimes additive packages are not very "mixable" among different brands and can
lead to deposits (also known as varnish) that can get in the way of proper
lubrication. Also (in my opinion) synthetic 20W-50 provides good lubrication, filming,
shear resistance, and extreme pressure protection for all 3 holes. Finally, if you put a gun to my head & told me I had to give up my mobil1...I'd feel just as good about using Amsoil.

Couple of suggestions- Anyone who has their professional life directly affected by lubrication
should know about a non-bias organization called Noria. I use them for my
&nbsp

 

viscosity chart

[IMG]local://upfiles/31141/9EE96F7297834D80AC7C0DA6D6264722.jpg[/IMG]

 

So, 75-90 gear oil is equivalent to 10-50 motor oil?

 

Of course to really soup it up there is the difference between Regular gear oil and Extreme Pressure gear oil.

EP for the Transemission but not for the Primary, is that right?Hell I forget.

 

I have been running Amsoil in my 2002 since new, even when HD said "do not run synthetic." At the first break in oil change I did run their non-syn lubes just for another 500 miles. I purchased all three seperate lubes at the time, they had a primary, engine and tranny. Just looking and smelling all three they appeared to be the same fluid with a different label.

I will admit, I did have a tranny problem at about 20,000, I did not tackle this fix myself as it was too hot and I wanted it together fast as my riding season is not very long here in MN. But the problem was a pressed in bearing in the tranny case came loose, I stopped riding it before the case was damaged. A friend of mine has the same bike only a 2001 (FXST) and he had the same issue and he runs the HD fluid, unfortunate for him he keptridingand messed up his case. So I beleive this was more of a press fit issue withthe tranny and not the oil.

I am just about to 30,000 miles and just changed to some chrome parts; the primary, cam cover and clutch release cover. So I have both primary and tranny fluids to put back in. This is why I am looking at this oil forum.

It does seem to make sense to run the gear oil in the tranny.

As far as the warrantly issue goes, they can say what they want, but they would have to prove the reason for the failure. I worked in the aftermarket automotive parts business for many years and this was always a conversation. They can not legally void your warranty unless they prove the problem was from running a different fluid, part etc..

 

You are correct! But, they always put the issue back in your court. You basically have to prove to them. All these scare tactics now days about voiding warranty. If in fact you did cause the problem, they can not void the entire warranty, only voided warranty is on that part or component system! So long as the aftermarket part, oil, etc. meets or exceeds the manufacturer requirements, they can not dictate to only use their brand. If so, they would have to cover service during the warranty period. Yeah, right!

Now then, anyone use Redline MTL for their trans??????