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Discussion Starter #1
This is the only vehicle I've ever owned that didn't give a gear oil rating for the final drive. It says "Hypoid", but no GL-4 or GL-5.....I see what everyone else is using, but I've just never seen this.
 

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I just changed mine and I believe I saw it in the Owners Manual. Can't remember exactly where right now though. I don't have my manual in front of me right now or I would look. :?
 

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"Hypoid" is not really a question of oil, so much as a question of gearcutting. Old (1920's) rear axles used straight bevel gears to form the crownwheel and pinion. These had two disadvantage, the pinion shaft meets the crownwheel on its central axis, and the straight cut gears are noisy. By using a more complex "hypoid" gear tooth shape (if you look at a pinion, the teeth appear twisted) these problems can be addressed. The more gradual engagement of the teeth along their length reduces noise. By careful design of the geometry the pinion can be made to mesh below_ the axis of the crownwheel. As the center height of the crownwheel is fixed by the wheel height, this allows the propshaft to be lowered relative to the car body, giving a clearer floorpan and lower center of gravity for better cornering, (OK not a BIG deal for a motorcycle). Hypoid bevels are now universal in this application.

Because of the sliding contact that hypoid gears make, their hydrodynamic contact pressure is higher. To be suitable for use with hypoid gears, a lubricant must be capable of resisting high pressures.

Oils with "EP" ratings (Extreme Pressure) such as EP90 are required. Some brands describe themselves as "hypoid" instead, a term which is synonymous with EP. GL-5 is a formal API standard for this type of oil (comparable to MIL-L-2105B/C/D)

Honda only states to use Hypoid gear oil, SAE#80 in th Shop Manual. There's little practical difference between 80 & 90 weights.

I personally run Amsoil Severe Gear 75w-90 Synthetic Extreme Pressure lubricant in the final drive of my GL1800 and in the final drive and the 2-speed sub-transmission of my 1980 CB900C.

 
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Use any 80-90 weight Hypoid gear oil.

And do yourself a favor and don't get caught up in the dino vs synthetic oil debate, because practically speaking it doesn't mean squat as far as your motorcycle is concerend, and will give you high blood pressure and indigestion, and pretty soon your eyes will glaze over. :roll:

Ride safe.
 

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montero1 said:
This is the only vehicle I've ever owned that didn't give a gear oil rating for the final drive. It says "Hypoid", but no GL-4 or GL-5.....I see what everyone else is using, but I've just never seen this.
My 05 owner's manual, page 137, says: type - hypoid gear oil; viscosity - SAE 80. I believe that's all you need because SAE (Society of Automotive Engineers) is the spec.

BTW, if you want to purchase the spec, go here: http://auto.ihs.com/document/abstract/YRWOXAAAAAAAAAAA. You may be able to find it for free somewhere? lol
 

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I do not go out looking for such things; but I do notice when I shop about. Its been a long time since I have picked up a bottle of gear oil that was not hypoid rated. Hard to imagine a maker stirring off a batch of non hypoid reciipe gear oil. You see; it would not matter one bit to a straight cut gear box if it had hypoid oil, in fact it may be quite a good thing for it; but a hypoid geared box with oil that would not take the high pressures would be toast early in life. Most all gear boxes run hypoid, unless you count trannies running on motor oil like our tranny does.

I wonder if the NGLI 4 and/or 5 specs don't assume hypoid or extreme pressure application. I do think synthetic has an advantage in that its rated viscosity is maintained so much better at very low and very high temps -- those long chains of synthetic molecular structure are the berries for us worry worts. :wink:

prs
 

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Discussion Starter #7
Well....

All the other bikes with final drives, and autos I've owned specified GL-4 or GL-5. I guess it's more important in a tranny, where most GL-5s don't work very well with synchronizers, and "supposedly" (I think it's BS) eat away at the yellow metals such as bronze and copper in the trans. I don't believe the last part, but I've experienced first hand about putting GL-5 in my transmissions. Cold weather shifting was so bad, I had to go from 1st to third, until it got hot. Had nothing to do with the weight, just the ep additives.
 
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