Transmission fluid [GL-5]bad for bearings : V-Twin Forum: Harley Davidson Forums

spgtti · 10-18-2009, 10:50 PM

After running Mobil 1 gear oil for 60,000 miles the bearings failed in my 5 speed. Gears were fine. A lot of research reveals many people believe GL-5 is bad for bearings and yellow metal[brass,etc.] and insist GL-4 is better but less available. Any comments?

doc ock · 10-19-2009, 02:22 PM

Recommended for use in differentials, manual transmissions and other gear applications requiring any of the following specifications: API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES 234 (Formerly Eaton PS-037), Mack GO-J, or the differential (hypoid) gear oil specifications from all domestic and foreign manufacturers such as GM, Ford and Daimler Chrysler. Can also be used in axles where an API GL-4 lubricant is recommended.

Amsoil

vindex1963 · 10-19-2009, 02:54 PM

Quote:

Originally Posted by doc ock

Recommended for use in differentials, manual transmissions and other gear applications requiring any of the following specifications: API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES 234 (Formerly Eaton PS-037), Mack GO-J, or the differential (hypoid) gear oil specifications from all domestic and foreign manufacturers such as GM, Ford and Daimler Chrysler. Can also be used in axles where an API GL-4 lubricant is recommended.

Amsoil

So that means it's ok?

FX-Rider · 10-19-2009, 04:51 PM

I bought a case of Bardahl GL-4 80W90 gear oil for my 100HP Dyna Wideglide for $1.99 a quart from Dennis Kirk.com ..great oil for a great price. and it shifts better than ever. i use there primary fluid and engine oil..

spgtti · 10-20-2009, 07:17 AM

This oil was developed for the extreme pressures of hypoid gears which are not common to Harleys. It has extreme pressure additives and a high sulfur content. Could there be a reason that Harley factory machines do not use hypoid gear oil in the transmissions? Bearing life maybe? "One must select the proper level of additives to maximize component life. A case in point is a manual transmission with bronze or brass synchronizers. Higher concentration of EP additives in manual transmission oils might cause the softer “yellow” metals (copper, brass and bronze) to wear out more quickly. API GL-4 contains approximately half the additive treat rate of GL-5. API GL-3 contains approximately half the additives of a GL-4. So which is better — GL-1 or GL-5? Again, the answer is neither or both. One must always select the recommended API designation for each specific application." [By Jack Snavely and Vatsal Shah ] National Oil & Lube News. More from a Ford forum-
To the best of my knowledge they are not interchangeable. The GL-5 has more Extreme Pressure (EP) additives than the GL-4 and different oxidizers. It is my understanding that GL-5 gear oils are for Highly loaded Hypoid gear differentials only. The Gl-5 can ruin bearings in a GL-4 application. As far as i know Harley has never used or needed high pressure additives or high sulfer content for their transmissions. Just questioning the recent year use of these oils. Harley might have a reason not to.

Night King · 10-20-2009, 06:07 PM

I´m using the German LIQUI-MOLY 75W-140 GL-5 Fully Synthetic Hypoid Gear oil in my 2009 FLHR 6 speed tranny.
It´s a German produkt! I don´t think they would risk putting this on the market, if it would damage any metals at all! (The Germans are like that, always make sure everythings safe; sicher!). It´s recommended for all gearboxes/differentials where spiral-cut/hypoid gearwheels are present. After all, our 6 speed trannies up to 2009 have 8 of ´em, and the 2010 trannies have 10 hypoid gearwheels! Getting neutral is real easy too, even the 5th gear whine is almost gone.

I´m also using their fully synthetic ATF in my primary; these oils are some of the best the market has to offer; (I´m going on reputation too). The first gear "clunk" is almost gone, even when cold, gear-changing and clutch action is now comparable to a metric or BMW bike.

Just my opinion
mike

DDuess · 10-20-2009, 07:05 PM

There are helical, but I doubt any Hypoid gears in a Harley trans...

Dan89FLSTC · 10-20-2009, 08:03 PM

No brass and no syncronizers in there to worry about.

Night King · 10-21-2009, 05:46 AM

Quote:

Originally Posted by DDuess

There are helical, but I doubt any Hypoid gears in a Harley trans...

Is there a difference?

DDuess · 10-21-2009, 02:15 PM

Quote:

Originally Posted by Night King

Is there a difference?

Yes, Helicals are normally parallel gear sets (like harley tranny) and are used to reduce noise (compared to spur or straight cut gears), can handle large loads, Hypoids are virtually always at 90 degree angles and are most common in automotive rear axle apps. Hypoids are on offset centers, and if they are on a common center, they are called spiral bevel gears, typically in front wheel drive cares due to more efficient power transmission then hypoids. Hypoids are used for large gear reductions and have a lot of sliding contact (shearing load), generate considerable heat. Helicals, not so much.

Night King · 10-21-2009, 04:24 PM

Ok, thanks for your expert explanation.
With all due respect, the reason I asked is, when I was serving in the British Army ´75-´84 in the Tank Regiment, I was responsible for helping rebuild a Chieftain tank gearbox; (that I trashed btw), and the whole thing was full of hypoid (and as you say, helical) gears. Some parallel, some at right angles, and we were told by our instructors that any spiral cut gear wheel, be it parallel or angled, is called a Hypoid. Maybe you call them different names in the US, I respect that, but to us they´re all hypoids. Btw, the sliding contact you mentioned, is the same, whether they´re at right angles or parallel, in fact it isn´t really a sliding contact, but more of a "squashing the oil along the teeth/grooves" contact. lol

I´m glad others have pointed out that our HD gearboxes cannot be damaged by GL-5 Hypoid oils. That was my main concern.

Take Care all
mike

vindex1963 · 10-21-2009, 04:41 PM

Quote:

Originally Posted by Night King

I´m glad others have pointed out that our HD gearboxes cannot be damaged by GL-5 Hypoid oils. That was my main concern.

Take Care all
mike

That's all I needed to know.

Dan89FLSTC · 10-21-2009, 09:13 PM

No brass, no synchros and no hypoid gears in in the transmission.
Helical gears, yes...Hypoid gears, no.

Hypoid gears are used to connect non paralell non intersecting shafts.

Ever notice that the driveshaft on your car/truck does not enter the differential at the center, but below the center of the ring gear?

They generate a lot of heat and rob power, but are just about the only game in town for high power transfer.

spgtti · 10-21-2009, 11:16 PM

The Harley transmission gears are pretty stout and they don't generate the extreme pressures and sliding action of hypoid gears. It seems the heavy hypoid gear oil is being used to cushion and quiet down the noise straight cut gears generally make and in some cases for claims of smoother shifts. What i am questioning is,is this the best lubricant for splash oiling the bearings? What metal are the bearing retainers or cages made of? Would a lighter oil like Harley Formula + be better for lubricating the bearings? I doubt a lighter oil ,although allowing for a noisier transmission,would actually hurt the gears themselves. These questions seem logical after a bearing failure using synthetic hypoid gear oil.

ViennaHog · 10-21-2009, 11:38 PM

Quote:

Originally Posted by spgtti

This oil was developed for the extreme pressures of hypoid gears which are not common to Harleys. It has extreme pressure additives and a high sulfur content. Could there be a reason that Harley factory machines do not use hypoid gear oil in the transmissions? Bearing life maybe? "One must select the proper level of additives to maximize component life. A case in point is a manual transmission with bronze or brass synchronizers. Higher concentration of EP additives in manual transmission oils might cause the softer “yellow” metals (copper, brass and bronze) to wear out more quickly. API GL-4 contains approximately half the additive treat rate of GL-5. API GL-3 contains approximately half the additives of a GL-4. So which is better — GL-1 or GL-5? Again, the answer is neither or both. One must always select the recommended API designation for each specific application." [By Jack Snavely and Vatsal Shah ] National Oil & Lube News. More from a Ford forum-
To the best of my knowledge they are not interchangeable. The GL-5 has more Extreme Pressure (EP) additives than the GL-4 and different oxidizers. It is my understanding that GL-5 gear oils are for Highly loaded Hypoid gear differentials only. The Gl-5 can ruin bearings in a GL-4 application. As far as i know Harley has never used or needed high pressure additives or high sulfer content for their transmissions. Just questioning the recent year use of these oils. Harley might have a reason not to.

Hypoid gear oil is just that, an oil to withstand the high shear forces in a hypoid design final drive. The HD trans does not feature this design and an oil specifically designed for this design may have characteristics that do not work well with the HD bearings. Too tigh viscosity ratings for the given application could have a similar effect.
Oils are purpose designed fluids and bigger numbers is not always better.......