For those of you who use the stuff, can you use one of them for both or do you need to use them separately? Example: use the primary fluid in both or primary in the primary and transmission in the transmission.

I ask because, as i知 sure most of you know, the Harley fluid (either the forumula + or the synthetic version of it) can be used in either cavity.

I have used their products before (both Amsoil and Harley), but I used the 20w-50 in my engine and transmission/primary on my 06 sportster. I知 thinking this time around I should use something that is designed for the particular application (primary/transmission).

 

Use what your owners manual calls for why pay more for nothing better most oils out here today are made with good quality additives and are well with in the standards

 

You make a good point. I didn稚 really understand why they (Amsoil) made 2 separate products when other manufacturers make one product that works for both.

 

KISS principle. today fluid manufacturers make a flavor for everything for marketing / revenue generation. Look at Mobil 1 website just under engine oil, my Lord there's a dizzying array of choices. I remember when Vodka was just Vodka and now they make everything from Peach Mango to Pomegranate Jalapeno! I just used what the manufacturer recommends for my auto and bike because it does the job

 

According to my dealer, says can use just 1 fluid in all 3 areas, no need to use anything but the engine oil in all 3 areas.

 

Your dealer is correct but the same fluid in all 3 holes isn稚 optimum.

 

I have used the Amsoil primary oil, and liked it. I also used their synthetic severe gear in my transmission and felt it was a good product. I'm one of the minority who do not believe 20w50 engine oil is suitable for primary and transmission application. I say this because I have suffered primary and transmission failures using 20w50 in them. I vowed to never do it again. If you only put a couple thousand easy miles on your bike every year, probably not an issue. I put quite a few mlies on my bike every year and a lot of it at 80mph interstate speeds. I currently use Red Line primary oil in primary and red Line Heavy Shockproof in my tranny. I realize not everybody thinks this is a reasonable or necessary step, but I hate having my bike in the shop for a month when the tranny shreds.

 

That was sort of my thinking. I reckoned that they wouldn稚 be making the stuff (primary/transmission fluid) just for fun. Or maybe they are, who knows. People way smarter than I am engineered the bike and all of it痴 subsystems, why question their recommendation?

I realize, of course, there is more than one way to do things like this. I致e been reading some fairly positive things about the Harley synthetic primary/transmission fluid.

 

Joe, I've been using AMSOIL for over 30 years and selling as an Independent dealer(in Canada) for nearly 25 years, just so you know where I'm coming from. I currently have a 2018 Anniversary Ultra LTD and use the three AMSOIL specific lubes in each hole. Here's a link to check the specs. https://www.amsoil.com/lookup/motorc...ume/?zo=331384
I believe it's better to use specific lubes for each different application...but now we have a common issue with the M8s Touring bikes (hydraulic clutch) transferring between the transmission and primary. The AMSOIL transmission lube isn't wet-clutch compatible, so herein lies the issue, should the fluid transfer from the transmission to the primary the result could become a slipping clutch too. This isn't an AMSOIL lube problem though, it is a HD MoCo problem. So since I currently have the specific AMSOIL lubes in the trans and primary I have to be vigilant in my oil level checks so that I catch any transferring issue early. Fingers crossed so far. This would be the case with many specific lubes by other manufactures too. So, the next oil change I do will be AMSOIL Vtwin 20W-50 in all three holes. This is what I recommend to all new HD customers as the first choice and AMSOIL recommends the same as well. The first choice in the above link shows this. I still prefer a specific lube for each application, but this transferring issue with the Touring M8s throws a wrench in the gears to this train of thought. Keep in mind that almost all metric bikes use the same lube in the same sump for the engine and transmission, like the Yamaha Roadstars and Stratoliners, Honda Goldwings, etc. They don't have transmissions blow up due to using a non-specific oil.
Hope this helps, Dutchy

 

Funny you say this, just a week ago you yourself were asking about the thicker gear lube from HD. So I understand, are you saying don't use aftermarket oil, or it's OK to use HD oils?