Why are people running GL5 gear oil in their transmissions?

[rich1]

Maybe I am missing something so help me out.  When HD started approving Syn3 motor oil in the transmission a lot of people thought they had lost their minds. But other manufacturers with integrated engine/transmission have been using engine oil for transmission lube forever. A lot of HD riders like to run hypoid gear oil in their transmissions. Seems to me that hypoid gear oil is no more appropriate for the application than 20W50 motor oil since Harley transmissions don't need the EP additives. So are people running the hypoid gear oil mainly to reduce noise?  I have nothing against using it but it seems the thicker gear oil could rob some power. Just looking for an alternative to Formula + which is nothing but over priced 50W mineral oil according to oil analysis. Thanks.

[chaos901]

I have no opinion on the GL5 Gear Oil in the title but I run Redline Shock-Proof in my bike transmissions. 

It clings very well, transmission shifts great and I never have had a problem.   

[HD95]

I run Amsoil 75-90 synthetic gear oil in mine.Smooth shifts,locates neutral precisely,quiet.I wouldn't run HD syn in anything.

[Slammers]

The way I look at it engines and transmissions have very different lubrication requirements. No one lubricant can do it all. There are trade-offs. If the you have an integrated engine and transmission you have no choice but to compromise. Having a separate transmission allows you to use a lubricant specially designed for that application.
Like Chaos, I use Red-Line Shockproof in the transmission. I feel I'm using the best product that is designed for the application.

[rbabos]

GL5 I believe has EP additives. It should not be used in any trans that has yellow metal bushings. The 6 speed is fine for it's use. Some earlier ones have bronze bushings I believe. In reality, there is no need for GL5 because EP additives only work under, well extreme pressure. The HD gear box won't really generate that kind of heat at any zones for the additive to actually work.
GL4 is plenty. Absolute bare bones of GL1 rated oil for the trans. I have a hard time believing Syn3 has a GL rating. Amsoil 20/50 does and has been used quite often in gear boxes. Me, I prefer a true gear oil for the gearbox.
Ron

[harley_cruiser]

It was explains to me by an oil expert that viscosity rating for gear lube was different than motor oil. That 20w50 was about the same as 75-90.
You do not want to use the 120w in any HD as it starves the inner bushing, as per Danny Peterson.

[WI Bob]

cruiser, you are correct.
I hand these charts out every week. http://www.golftechs.us/Reference/viscross.pdf

[PeteH]

Thanks for that chart!

Gear oil for unsynchronized gnashing gears, same as my lower units.

[mr. pitts]

The way I look at it engines and transmissions have very different lubrication requirements. No one lubricant can do it all. There are trade-offs. If the you have an integrated engine and transmission you have no choice but to compromise. Having a separate transmission allows you to use a lubricant specially designed for that application.
Like Chaos, I use Red-Line Shockproof in the transmission. I feel I'm using the best product that is designed for the application.

+1 on that. I put HD primary/tranny oil in my tranny (96 Electra) kept it in for 50 miles. The tranny was as rough as hell. Changed to Redline shock proof heavy & it's as smooth as butter. Gonna change to Redline primary oil (in the primary) when I've run out of HD oil.

[mp]

I don't know why anyone would want to mix their engine oil with their transmission lube.  It only makes sense to use gear oil to lubricate gears.  And the weight ratings of gear oil are not comparable to the weight ratings of engine oil.  A 75w90 gear oil is about the same viscosity as 10w40 engine oil.

[bigfoot5x]

I did not know that gear lube ratings were different than oil ratings. I wondered how 75w90 gear lube could be replaced by 20w50 Syn3 and have it work. The numbers just never made sense to me.

[Don D]

The viscosity numbers never will make sense because the pour points of a 75W gear oil is about the same as 30W motor oil.
It is a constant mesh gearbox, no syncros, and there are many oils that will work well but not motor oils.
Ron has this nailed

[pumpguy68]

  motor oil is for motors. Gear oil is for gears!


Ray m

[Latrobedyna]

The standard saybolt system either SUS or SSF is the best way to determine viscosity. Sadly most retail marketed oil products lack such information on the containers.

[shovelinabox]

I have no opinion on the GL5 Gear Oil in the title but I run Redline Shock-Proof in my bike transmissions. 

It clings very well, transmission shifts great and I never have had a problem.

[truck]

When you don't use the right gear oil, your bike could catch fire, like these windmills.

[attach=1]

[attach=1]

[attachimg=3]

[BUBBIE]

A GL5 rating Gear Oil;  Will Take Heavy Gear Pressure...

extreme-pressure protection of a GL-5.

signed....BUBBIE

[Ultrashovel]

Hmmm, I've used the heavy Redline in my HD transmissions ever since I can remember.....whenever I first heard about it on the market. I've never had a problem with a Harley Transmission. I don't like Syn 3 but it's not something that I would use in a transmission in any case. It's motor oil.

[Big Cahuna]

Oh my God, I've been using GL-5 rated oil for years. When am I gonna start having problems?.,,,

[dr. evil]

Tomorrow.

[Dan89flstc]

Metric bikes have been lubricating transmissions with engine oil since the beginning of time, their gears hold up fine, and transmit a lot of power in many instances.

Theoretically it would seem that gear lube would be the only thing to use. I have never seen a gear that was worn out due to lube failure in a Harley transmission, no matter what the lubricant used, but I have seen many trashed bearings....maybe the gear lube is the wrong lube for the bearings   

I don`t think it is a big deal what you use in these low stressed gearboxes.

[Ultrashovel]

I'm going to add this issue of transmission lubricant to my list of things not to worry about. 

[motorhogman]

 

I'm going to add this issue of transmission lubricant to my list of things not to worry about. 

   

[BUBBIE]

Our Harley Gears are NOT little, light nor Wimpy gears... Gears WILL Chew up motor oil molecules not meant for in between gears... It chews them up and no spitting them out.

I will only use what HAS worked for so many For Years.... Redline ShockProof...I prefer the Heavy...

signed....BUBBIE

[PoorUB]

Better to use a lube that is " over rated" than " under rated"

[Soft 02]

Oh my God, I've been using GL-5 rated oil for years. When am I gonna start having problems?.,,,

When the bronze plating starts flaking off your shift forks.

[bigfoot5x]

I used Syn3 in the tranny and primary for a few years with no problems at all and I put plenty of miles on the bikes. I switched to Syn3 when it came out because I was riding a Dyna and my wife had a Sportster. At that time I had 4 different fluids to keep track of because of Sport Trans fluid, primary fluid, Tranny fluid and engine oil. What a hassle. Now I just use Formula+ and Syn3. The dealer gives me enough of a discount to match Mobil 1 so I'm good. I've always figured that Harley would not make recommendations that would harm their bikes. Wouldn't that be bad for their business if they all started breaking?

[Barrett]

http://www.spectroshop.com/6-speed-transmission-oil/cat_7.html
I've been running this since my first oil change and all is well.. It looks clean when I change it and there's no debris on the plug..

[chopper]

motor oil is for motors. Gear oil is for gears!


Ray m

Yup. aint rocket science.

[Dan89flstc]

Oh my God, I've been using GL-5 rated oil for years. When am I gonna start having problems?.,,,

When the bronze plating starts flaking off your shift forks.

In other words...never.

[Soft 02]

Nope. Probably not. My brass coating was flaking off when I rebuilt mine but I doubt it was due to running gl5 in it.

[rbabos]

A GL5 rating Gear Oil;  Will Take Heavy Gear Pressure...

extreme-pressure protection of a GL-5.

signed....BUBBIE

When dealing with Amsoil to come up with a specific primary fluid, pre Compensaver days,  which they now have,  GL5 came up at one point. The HD gear box is incapable of gererating enough friction to make use of the additive. The clutch on the other hand was. GL4 is all you need. Actually GL1 is more then enough. Having a v rod that uses the same oil for engine and trans, I decided to stay with Amsoil with the GL1 rating. While most any dino oil, clutch rated will work, the gears will chew the crap out of the molecules in short order. The reason I never went to Shell Advance oil. True PAO oils are very shear stable so I get the best of both worlds in this case.
Note that even though Amsoil has a primary fluid, a delivery system is still needed for the comp.
Ron

[Ultrashovel]

I can think of one good reason for using a heavier lubricant in the transmission. It is thicker when cold and, if you pull your clutch in for about 10 seconds when going into first gear, it will drop right in with no clunk.

I've always been amazed at how strong the gear dogs must be in a Harley transmission to put up with all of the abuse. I watch riders all of the time, like when I'm at a gas station or restaurant. They will come out, start their engine and then smash their big fat heavily booted hoof down on that shift lever like they are mad at it. You can hear the clunk 100 yards away, too. I always wondered why they do that?

Anyway, with the heavier oil, like Redline, I have fewer clunks, even when hot.

[garyajaz]

when talk of redline was first read here by me I changed over to it.
the last 10 years been running it. less clunk no problems every thing just fine.
I putting new shock heavy in when my 95 build is done.
also MTL in primary.  same story 10 years and not a problem.

on a side note I put a belt drive in my ironhead maybe 35 years ago.
it spit belts every month or so (yeah, I was drag racing)
factory said it should not happen. they were having problems with all of them.
turns out the detergents and stuff in the oil killed the belts.
sooo, in went the non detergent 40 wt.
been in there all these years.  shifts fine and the Barnett clutch dosent seem to care.

[Mark P]

I like spiders in my oil.

http://bakerdrivetrain.com/wordpress/wp-content/uploads/2011/10/IW_1011-Oil-and-Spiders-Baker-Drivetrain.pdf

[r0de_runr]

Some 07 later bikes have an annoying rattle while hot, in neutral.  Harley Service Bulletin says "Normal."
I had it on my 12 SG SE, until I replaced whatever was in the tranny with 75W140 Synthetic.  Now no rattle when hot in neutral, at least not from the tranny.

[Admiral Akbar]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

[Bigs]

I've been using Amsoil 75W-110 severe duty in my '11 RGU for over 30,000 miles without any problems and my '06 RG for 40,000 miles with no problems. I started using Quicksilver 20W-50 V-Twin synthetic oil in my primary mainly because I get a four gallon bottle for $25 at Walmart, so far so good. It might be OK for the engine but I'm using Amsoil and when I run out I'll use Mobil 1.
Aren't these oil threads nice. 
   Bigs

[Dan89flstc]

  They will come out, start their engine and then smash their big fat heavily booted hoof down on that shift lever like they are mad at it. You can hear the clunk 100 yards away, too. I always wondered why they do that? 

To put it in gear...

Those guys aren`t the people who go on forums and whine about the clunk.

[rbabos]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

Not really but it would freak most people out seeing the gold metal flake in the oil in bright sunlight. Again depending on application. Shift bushing no big deal. Trying to make a thrust washer for the comp out of bronze, not great idea.  No issue with gear oil in general, just the additive in GL5. There is no gain to going GL5 in the crunch drive as the additive never gets used. Not enough friction.  Just about all GL1-GL4 are harmless to bronze based bushings, synro rings or whatever.
Ron

[Ultrashovel]

  They will come out, start their engine and then smash their big fat heavily booted hoof down on that shift lever like they are mad at it. You can hear the clunk 100 yards away, too. I always wondered why they do that? 

To put it in gear...

Those guys aren`t the people who go on forums and whine about the clunk.

You're right. But they are probably the ones who get their transmissons rebuilt now and then. 

[Dan89flstc]

I like spiders in my oil.

http://bakerdrivetrain.com/wordpress/wp-content/uploads/2011/10/IW_1011-Oil-and-Spiders-Baker-Drivetrain.pdf

I just read that article...

"As temperature increases, the spider's legs open up and
connect with the "legs" of other polymer molecules, making the oil
thicker and increasing viscosity.  This is how oil can change weight
from 75 to 140 with a change in temperature."

The oil`s viscosity never increases as the oil gets hot, it never gets thicker as it gets hot.

It`s suprizing how many people do not understand multi grade oil, and this article will not help them.

[Admiral Akbar]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

Not really but it would freak most people out seeing the gold metal flake in the oil in bright sunlight. Again depending on application. Shift bushing no big deal. Trying to make a thrust washer for the comp out of bronze, not great idea.  No issue with gear oil in general, just the additive in GL5. There is no gain to going GL5 in the crunch drive as the additive never gets used. Not enough friction.  Just about all GL1-GL4 are harmless to bronze based bushings, synro rings or whatever.
Ron

The different bearing bronzes that are available fail the litmus tests for a thrust bearing by quite a bit.. Only possibilities are needle bearings or plastic thrust washers like PEEK or Vespel.. It wouldn't surprise me if the needle bearing is cheaper which is why HD choose it for production.. 

[Admiral Akbar]

I like spiders in my oil.

http://bakerdrivetrain.com/wordpress/wp-content/uploads/2011/10/IW_1011-Oil-and-Spiders-Baker-Drivetrain.pdf

Bet you ca see em real well after a couple tabs..    Bert's an interesting guy fer sure... Very smart and a bit eccentric..

[BUBBIE]

 

WELL,,,,,You should TALK

signed....ANONIMOUS

[Outerlimits]

Was talking to a guy at a Harley Dealer that said his 05 Classic was in for its 3rd compensator. He had about 65000 miles on it. Said the tech told him the reason that he was going thru compensators was because of that "Redline Stuff." The gear oil is too thick causing to much drag in the transmission and wearing out the compensators. I asked why he kept running the Redline Shockproof then, he said think of how many more he would have had to replace if it wasn't for the Redline oil. I said good point......and excused myself.

[rbabos]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

Not really but it would freak most people out seeing the gold metal flake in the oil in bright sunlight. Again depending on application. Shift bushing no big deal. Trying to make a thrust washer for the comp out of bronze, not great idea.  No issue with gear oil in general, just the additive in GL5. There is no gain to going GL5 in the crunch drive as the additive never gets used. Not enough friction.  Just about all GL1-GL4 are harmless to bronze based bushings, synro rings or whatever.
Ron

The different bearing bronzes that are available fail the litmus tests for a thrust bearing by quite a bit.. Only possibilities are needle bearings or plastic thrust washers like PEEK or Vespel.. It wouldn't surprise me if the needle bearing is cheaper which is why HD choose it for production..

Quite possible cost was the factor but in some ways just going metal to metal would have worked just as well in that application and cost nothing. All prior comps and even that POS 07 version ran that way. Thrust surface would still likely outlive the spokes.
Ron

[Admiral Akbar]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

Not really but it would freak most people out seeing the gold metal flake in the oil in bright sunlight. Again depending on application. Shift bushing no big deal. Trying to make a thrust washer for the comp out of bronze, not great idea.  No issue with gear oil in general, just the additive in GL5. There is no gain to going GL5 in the crunch drive as the additive never gets used. Not enough friction.  Just about all GL1-GL4 are harmless to bronze based bushings, synro rings or whatever.
Ron

The different bearing bronzes that are available fail the litmus tests for a thrust bearing by quite a bit.. Only possibilities are needle bearings or plastic thrust washers like PEEK or Vespel.. It wouldn't surprise me if the needle bearing is cheaper which is why HD choose it for production..

Quite possible cost was the factor but in some ways just going metal to metal would have worked just as well in that application and cost nothing. All prior comps and even that POS 07 version ran that way. Thrust surface would still likely outlive the spokes.
Ron

So why didn't the compensaver go back to a hardened steel thrust washer instead of PEEK  system if it's the answer?

[rbabos]

Anything wrong with using yellow metals in the primary if gear oil is avoided?

Not really but it would freak most people out seeing the gold metal flake in the oil in bright sunlight. Again depending on application. Shift bushing no big deal. Trying to make a thrust washer for the comp out of bronze, not great idea.  No issue with gear oil in general, just the additive in GL5. There is no gain to going GL5 in the crunch drive as the additive never gets used. Not enough friction.  Just about all GL1-GL4 are harmless to bronze based bushings, synro rings or whatever.
Ron

The different bearing bronzes that are available fail the litmus tests for a thrust bearing by quite a bit.. Only possibilities are needle bearings or plastic thrust washers like PEEK or Vespel.. It wouldn't surprise me if the needle bearing is cheaper which is why HD choose it for production..

Quite possible cost was the factor but in some ways just going metal to metal would have worked just as well in that application and cost nothing. All prior comps and even that POS 07 version ran that way. Thrust surface would still likely outlive the spokes.
Ron

So why didn't the compensaver go back to a hardened steel thrust washer instead of PEEK  system if it's the answer?

NOISE.
Ron.