Transmission oil

[Lakeman]

I'm sure no one has ever talked trans oil here, so here goes. I want the best lub I can get for my trike. Harley recommends 20w-50 for the trans and a lot of people here use Redline 90w-140 and say it works good and makes the trans quieter. Why would anyone run 90w-140 when the manufacturer recommends 20w-50? You could add a half cup of sawdust and it would also run quieter but I don't want to do that. Yes I would like to have the trans run quieter but not sure about the 90w-140. The guy I bought my trike from always ran synthetic oil in all the holes but the last time he had it serviced he didn't use the synthetic as he was selling the trike. After a few hundred miles I changed everything back to synthetic 20w-50 and the trans was quieter at first but not so much after 2000 miles. With the 90w-140 I would be concerned the heavy oil may get into the tight tolerances of some of the parts. Can anyone tell me why I should run 90w-140?

[KRUZR]

After asking my dealer about how noisy my trans was in 2007, they suggested we try Belray 75W140 gear oil for the trans and it helped. Just before I left for the Trike Talk Rally this year, I changed the trans to AMSOIL 75W140. To my surprise I started getting 2 to 3 more MPG. Needless to say, I'm sticking with the AMSOIL in the Trans. Also before the Rally I put 60W AMSOIL in the engine that I just changed out, but normally use AMSOIL 20W50, and I have always used Formula Plus in the Primary. Ride Safe!

[americanbadass]

I tried the 75w140 in my 2003 Roadking Tranny and found it to be sluggish-ran it for a few hundred miles before switching back. I guess once you get used to the way something feels, it's hard to change. This theory applies to everything but women!

[msocko3]

I can't bring myself to run motor oil in my transmission. When the HD dealer had me talked into Syn3 in all 3 holes I did it for awhile, I was surprised at the metal fuzzy stuff on the drain plug magnet. I switched to Redline Shock proof heavy and never saw anything on the drain plug magnet again. I think any good synthetic 75-140 will work just fine.

[rap47]

Why run gear oil in the trany?..... Because the trany is full of gears!

[trikermutha]

Been running amsoil for a long time now..Been working for me ok..

[jcolson]

I use 75-140 Amsoil. Shifts smoother.

[GARYD]

When I had a 6 speed put in my 03Ultra, the dealer put in BelRay 140. '
I have and always will use Amsoil products until someone can show me something better and CHEAPER. At that time I will probably change.
In the meantime, I, like, KRUZR use Amsoil 20/50 in the engine, Amsoil Severe Gear 75/140 in the trans and H-D Formula+ in the primary.

I don't think you will have any problems using ANY 75/140 GEAR oil.
I would not use an engine oil in a transmission.

[FLTR2008TRIKE]

Here is link that will explain the differences of gear oil vs engine >> AMSOIL Article - Gear Oil Basics

Personally I use Amsoil MC 60wt Synthetic for my engine and primary oil and I did use Amsoil Severe Gear 75/140 gear oil in my transmission.

I now use Redline Shockproof 240 gear oil in my transmission which looks like pepto bismal. Reason for that change was the shear stability was a little higher then Amsoil

I did a oil analysis after my road trip in 2008 from Myrtle Beach SC to California and back. I had my engine oil and my transmission oil checked. After 8400 miles the Amsoil Severe Gear oil in my transmission was needing to be changed

[1852cc]

I have never bought into, the idea of motor oil in the transmission.
I have been running Mobil 1 synthetic's, in all holes, never liked the HD oils.
I run 20/50 in the motor, 75/90 in the transmission (winter) and 90/140 in the Arizona heat.
The primary is 10/40, but I dont run a stock clutch either, have Rivera Pro Clutch.
I would have never ran motor oil in a standard transmission, or rear end, of a vehicle, so why do it to a motorcycle.
I have been riding 50 years, and about 80 per cent of that on a Harley of some sort.

The point is, its your vehicle do what you want to it, above is just what I do!

[greyfang]

at 10000 miles, I switched to Castrol Power RS 20W50 full synthetic in all 3 holes. Transmission seems to shift smoother now.

[Gorilla]

I'm not an expert but I thought I read somewhere that the rating numbers for engine oil (20W50 or whatever) did not mean the same think as the numbers for gear oil (75W140 or whatever) I believe I read that in an AIMS OIL publication. I'm not sure if I read it correctly but that is sticking in my mind. Either way I use synthenic gear oil in HD 75W140 without issue.

[Gorilla]

okay I took the time to look it up. My memory was wrong here is the skinny for those who do not know:

Multi-Grade<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o></o>

• To account for changing temperatures oil is manufactured through the use of additives so that it can have multiple grades of viscosity, or multiple weights. One weight will be a winter weight and the other will be the hot weight. So you may see gear oil listed as "75W-90" which gives you both the winter and hot weights of the oil. Instead of switching out the oil during the year to compensate for the changing temperatures, most equipment will allow a multi-grade oil to be used year-round (check your manufacturer's specifications to be sure).<o></o>

1. Gear Oils<o></o>

o An oil's use can be determined by the SAE number or grade it is assigned. Numbers of 60 and higher indicate gear oil while lower numbers indicate engine oil. This means 75W-90 and 80W-90 are both gear oil.<o></o>
</SECTION></SECTION></SECTION></ARTICLE>

[Ozarkryder]

I've had a chuckle about the MoFoCo oil policy. We could have a long philosophical discussion on enginering and marketing on lubricants and why a product is recommended. For years we were cautioned to not use synthetic oil of any kind in any HD anywhere. Seems that the synth oil was too slippery and would cause bearing skate, bushings would wear and on and on. Then comes the day HD releases their own synth, and all of a sudden the same product is OK in all three cavities of the Big Twin, not just for the Twinkies, but it is good for Evos and older bikes too.
Me, in the tranny of my '90 FLHS, I like Royal Purple 85W140. We have mild winters in SW MO so I use it all year. A slight bit noisy until the tranny warms up in the winter, but good protection. When I lived in Minnesota we had cooler temps and I used their 75W90.

[Phu Cat]

Gorilla, An oil's use can be determined by the SAE number or grade it is assigned. Numbers of 60 and higher indicate gear oil while lower numbers indicate engine oil. This means 75W-90 and 80W-90 are both ge

Mostly correct. Even tho engine and gear oils may be close in viscosity, tranny oil has aditives that are nor rercommended for engines, and engine oils can't provide the lubrication that gears require. So lube oils are rated with different numbers that make it easy for 'Joe-consumer' not to get mixed up.

Just for the record, gears put WWAAYY more pressure on its lubricant that engines do. That's why using engine oil isn't recommended in trannys. Having said that, how long have jap bikes been getting away with bathing their tranny in the same oil the engine uses???

My expensive HD only gets the best.

Phu Cat

[Ozarkryder]

My expensive HD only gets the best.

Phu Cat

Which is.....?

[Lakeman]

What he said!

[Phu Cat]

Ozark, Oil that's designed for the tranny in the tranny, and oil that's designed for the engine in the engine.

Can ya use any oil in an hole? Sure. It's not a matter of whether you can use a specific oil somewhere, for me it's more a matter whether you should.

Ya gotta think Harley's saying their oil can be used in all e holes is nothing less than a market scam to aid their oil sales.

Phu Cat

[Lakeman]

OK everyone has me convinced, thanks for all the input. I think I'll try the Redline Heavy shockproof gear oil. They don't say what weight it is, why is that? They say film thickness greater than 75W-250 but low fluid friction like 75W-90? What ever the hell that means. I guess I am correct that the transmission (5 speed) is wet sump with splash lubrication. Again thanks to everyone.

[icebite1]

In the end its what you think is best, everyone has theie own opinion/favorite.
Mine is RedLine Heavy Shockproof, I have tried most of the others and now use it in five of my HD,s. I also use their Primary oil.
Give it a try, you can always change to something else.
Its not sold locally here so I buy it online at Racer Parts Wholesale - Racing Parts, Safety Equipment & Motorcycle Accessories , primary and tranny oils are not changed that often so its not a big deal for me to do it that way and I just order enough of each for free shipping.