Trans oil viscosity ratings are different than motor oil , it is lighter ( thinner ) .. IOW a 75w viscosity trans oil is not as think as a 75w motor oil . I wouldn't worry about it . .. And do use a multi viscosity ..
I have used the Harley oil , Redline and Belray , actually like BelRay the best myself .. But thats neither here nor there ..

 

Was just wondering because it seems to be popular at my local dealership, might give it a shot.

 

I use Amsoil 75-140 in the transmission and it works great. Been using it almost since owning the bike. I will use it again when it's time to change it.

 

Same here. Never a problem.

 

If you can run Syn3 in a cruise drive, you can run just about anything in there.

Personally on the older ones I like Redline with Shockproof. On the M8's I'm inclined to stick with the Formula+ it came with. Since there is a chance that some of it could end up in the primary.

 

I also use BelRay Big Twin Transmission Oil in My 2012 Custom and really like it. I changed from Redline Shock Proof and am very pleased.
Mike U.


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Also run 75w-140 Gear oil in all my Harleys. The moving parts are gears sooooo.

 

I run the AMSOIL V-Twin Transmission Fluid in mine, it works great!


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I've used 75 w 140 full synthetic gear lube in the trans either Mobil 1 or Valvoline in my 08 since the bike was new and I haven't had any transmission problems yet and the bike has over 100,000 miles.

 

I run 75w140 Mobil 1 synthetic in all of our own bikes.

 

Pretty much what I thought as well, since new I have always run Amsoil 75w-110 and will continue to, I definitely would not run Syn 3, thay stuff is crap IMO, too many horror stories as well of bearing damage, gear lube like Amsoil is the way you go.

 

There are probably as many opinions on this as there are for what engine oil to use. I've run everything from Syn3 to Redline with Shockproof to different brands and weights of gear oil. They ALL work and I haven't seen any real proof that any of them are a cause of any kind of failure when something does. The gear oils do seem to help make the shifting quitter but there are some mechanics that say it's not the best to use because of the bearings. If bearing failure is my biggest concern then gear oil would not be my first choice. I would be using something that is formulated by whatever manufacturer for Vtwin transmissions weather it be Amsoil, Belray, Redline, or even the HD Formula+. If you don't like Syn3 that's fine but there have been some members on here that have sent it in for their own independent testing and it tested just fine as far as an engine oil. Haven't seen any testing in a tranny. I don't believe that if the fluid makes the transmission sound quieter for shifting that it automatically makes it a better fluid for the longevity of the parts. Even if I like the sound better it doesn't make it a full proof test of how good it is actually working to prevent any kind of premature wear on the gears, slider dogs/forks or bearings.

 

Transmission in the HD is basically a gear box just like in the auto and truck field, I would definitely not recommend syn 3, way too thin for gears, that's based on science, gear oil 75W- 110 is recommended by amsoil as well as other companies, way better option, most of the the transmission bearing failures are due to lack of lubrication, regular oil doesn't cut it.

 

Understand that I'm not advocating one lube over the other as I am just stating there are various choices depending on what your theory is. What I don't understand is that how a 20w/50 engine oil can be the best for bearings everywhere else in the engine but will not cut it for the bearings in the transmission. I get wanting to use the gear lube because of the gears, that would seem to be a no-brainer, but is a straight gear lube adequate for the bearings? I just looked up what Amsoil suggest for the V-twin (I did a search by vehicle and selected a 13' FLTRX) and no where did I find 75w-110 in their results. They suggest their 20w/50 Synthetic V-Twin Motorcycle Oil or their Synthetic V-Twin Transmission Fluid. Now I'm not pushing their product and I am just stating what comes up on their site. My whole point hear is not to argue or convince any one fluid is better or worse than the other just that there is more to consider than just the gears when selecting a fluid. I have a friend that has more than 120k on a 2012 Ultra Classic and he has ONLY used Syn3 in the tranny with no issues. I also know people that have used primarily gear lube and have had the dreaded bearing failure at under 50k miles. I have personally used gear lube for more than 70k in a bike and never experienced any problems. These days I will just stick to Formula+ or the Amsoil Syn Trans Fluid. Others that are designed for V-Twin trans are fine too. That doesn't mean that I would worry about putting a gear lube in my transmission. It only means I have tried them all and I have decided to just stick to that type of fluid for now. If someone doesn't like Syn3 that is fine. There are plenty of choices that they can rock in their tranny.

BTW... If anyone has some proven data that a particular fluid IS the cause of any type of HD transmission failure please post it. I have only seen theories, some I can buy into and some not so much but still they were only theories or opinions.

https://www.amsoil.com/lookup/motor...otorcycle/2013/harley-davidson/fltrx-road-glide-custom/1690-(103-ci)/us-volume/

 

Another oil thread. Gear lube and engine oil are rated different so 20/50 and the gear lube you use are about the same. You can run F+. 20/50 standard oil or syn. you can run Redline , belray or any other you wish in the end it will make no difference what so ever. Many have put over 100,000 on these gear boxes running F+. Comes down to what helps you sleep at night.
With 3 bikes I gave up, 1996 EVO, 2015 Street and the 2017 RGU I went M1 20/50 all 3 all bikes one lube to deal with. Long term bet they won't care on bit. The Street is one of those you pull one plug and dump oil in so simple. No Syn will not destroy the clutch.

 

Crisco

 

I'm actually running that in my 18' FLTRXS now and I find that there is no migration to the primary whatsoever but the fried okra is not getting as crispy as I like it.


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I hear ya totally understand and respect your point of view, I spoke to amsoil rep directly a while back and this was recommended to me because 2011, also my dealer where I bought my bike from , maroneys in Newberg NY, owned by Teds cycle, the tech there has last knowledge and he recommended this as well, formula + is good stuff it's about 80 wieght oil, 75w110 starts out thinner and as it heats up becomes more like 110, actually protects better on cold start up than regular formula + , but I hear run what you like, but motor oil to me is on the thin side, after 30 years as a technician in the auto and truck field, as well as working on motorcycles I have seen people run pretty much everything but the majority of people that I have run across as well as a good indy shop I am friends with they all frown upon motor oil in the transmission. But I understand your point, which is a very good one.

 

"75w110 starts out thinner and as it heats up becomes more like 110, actually protects better on cold start up than regular formula + , but I hear run what you like, but motor oil to me is on the thin side,"

All dual weight motor oils have molecules that expand as they heat up making them a higher viscosity hence the reason they are dual weight. Yes it is true that motor oils are of less viscosity than gear oils but these transmissions do not have even have close to the load of a diesel truck so is thinner a bad thing in this application? I can't scientifically answer that but I do know that the MoCo recommends either the Syn3 or Formula+ and they wouldn't do that if either of those were proven to cause premature failure and they had to pay out in warranty claims. Who knows? Maybe they would. Lol!

Just as an FYI, the Amsoil VTwin Trans Fluid properties are:

TYPICAL TECHNICAL PROPERTIES AMSOIL Synthetic V-Twin Transmission Fluid (MVT)
Kinematic Viscosity @ 100°C, cSt (ASTM D445) ......................20.7
Kinematic Viscosity @ 40°C, cSt (ASTM D445) .......................190.3
Viscosity Index (ASTM D2270) .............................................127 Pour Point, °C (°F)
(ASTM D97) ......................................................................-40 (-40) Flash Point, °C (°F)
(ASTM D92) .....................................................................228 (442) Fire Point, ºC (ºF)
(ASTM D92) ......................................................................242 (468) Four-Ball Wear Test
(ASTM D4172 @ 40 kgf, 150°C, 1800 rpm, 1 hr), Scar, mm .....................0.55
NOACK Volatility, % weight loss (g/100g) (ASTM D5800) .........................8.43
Foam (ASTM D892, Sequence I, II & III) ................................................0/0/0

I post this as an example, not to advocate it. It is the information you would want to try and understand & compare between the different types of fluids to make an educated choice. If you really care about the nuts and bolts of it that is. If not, just run want and ride on.



***I apologize for not being able to find the Tech Properties of the Crisco as a comparison. I'll keep looking while I finish my MM Cask Strength that I just happen to be sipping on at 1030 in the morning. Don't judge me....>

 

And also Amsoil did change there product listing on Harley transmission fluids because they have a specific fluid now for trans with no viscosity rating, I think it's just another version of formula + but synthetic, they used to have 75W-110 severe gear listed.

 

Good info, love it, that's what makes this forum so informative, the sharing of knowledge and real world experience, but one thing I have learned as a final note from automotive companies as well as Harley, they will push there products, and keep in mind , there products are more budget minded that longevity, everything is made withing there budget, so IMO there will always be a better option than the stuff the MOCO sells, do you know why they push syn 3 on the M8s has nothing to do with warranty and more because of there fluids intermixing, that's a statement by a good friend of mine who is a SE tech at Harley.

 

Good info, love it, that's what makes this forum so informative, the sharing of knowledge and real world experience, but one thing I have learned as a final note from automotive companies as well as Harley, they will push there products, and keep in mind , there products are more budget minded that longevity, everything is made withing there budget, so IMO there will always be a better option than the stuff the MOCO sells, do you know why they push syn 3 on the M8s has nothing to do with warranty and more because of there fluids intermixing, that's a statement by a good friend of mine who is a SE tech at Harley.

Indians use one oil for all 3 compartments.
One drain and one fill hole. Maybe this is Harley's way of slowly morphing into what Indian does... :grin:

-

 

I think it's just from a cost perspective , JMO.

 

I went from Royal purple to Redline shockproof and didn't notice any difference - both seem to work great

 

Harley just came out with a 80-140 gear oil that they claim is also primary usable. I don't know of anyone who has tried it yet.

 

I just put this down the hole in mine today. I have a migration issue so I am looking to see if this makes it better,worse or same

 

Gear Oil

I have been using 75w140 Spectro for years now and I love the way the bike shifts with it in the trans. My bike was in the dealer for about a month and a half so they could fix several problems. First of all was the clutch recall and then the transference of oil from the trans to the primary. While the heavier gear oil slowed the transfer down a bit, it did not stop it. So when the bike went to the dealer for the clutch recall, I also directed them to do something about the fluid problem. On my bike the transfer had already been documented since new. So, they put a bigger clutch rod in the trans and had to ease the trans door for it to operate. They then put a seal in the trans behind the clutch to stop the sumping. I got the bike back just before the weather started to suck and have only ridden it once since then after I installed the new Ohlins from Smarty.
To be honest, the bike didn't have fluid migration unless I rode it really hard and I haven't been able to determine if the transference has been stopped as yet because of the weather.
Since the trans on these bikes get so hot during use, I am sold on using the heavier synthetic oil in the trans, and using Formula+ in the primary. It just makes sense to me that it holds up better than the thinner gear oils.
You should use whatever oil you feel comfortable with but be aware of what is out there.

 

I’ve used lucas 80/90 75/140 and don’t notice a difference.Ive used other brands but I do use a quality gear oil.

 

I have been a die hard Amsoil rider for the last 9 years had my bike at the Indy for a k service he was all about Belray I said fine ... I have to admit I like these fluids 107 build seems Quieter temp never over 245 he said Belray makes nothing but motorcycle lubes just my 2 cents ride safe

 

2015 RG.

Has anyone tried Royal purple gear oil I think I will go with amsoil but just curious?