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R18 Classic - Hypoid Axle Gear OIL GL3 ... or 5? ... or 2?

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Witsend

Witsend

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R18 Classic 2023 and Vulcan S 2020
Learning how to do 600 mile service on 23 R18 Classic.

Watching a vid the guys uses GL3. Does it have to be GL3? The only GL3 I can find is BMW OEM at a ridic. price of $57. :(

GL5 way more affordable. See below

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I'm not a chemical engineer; with that said, I try to adhere to BMW's recommended specifications for lubricants when maintaining my bikes and I'm not sure about the difference between the 3, 2 or 5 designation. This is mostly to stay within the warranty parameters; however, I'm pretty sure that if you use a different brand that has the same specifications as what the BMW brand states, you're good warranty wise.

I typically buy my annual fluids in bulk (1 to 2 years worth) when BMW shops offer discounts during the Holiday Season.
 
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For what its worth ... I use Bel-Ray 80-90 'Hypoid' ... 17000 miles and no ill effects from what I can tell ... in other words, nothing on the magnet and no 'cloudiness' in the oil when changing it ...
 
Ok, not to geek out.... But.

On this video he shows Hypoid Axle Oil G3 SAE70-80 GL-5

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But... On this thread a post states:

"G3" sounds like a spec for a particular type of oil, but it is not. It just the name of one company's (BMW) gear oil.

API GL-5, 70w-80 or 75w-90, LS or non-LS, your gears will be happy and no dealer will question warranty eligibility on the basis of the oil.

On another thread here seems any 70W-80 GL5 would work... problem is the only 70W-80 GL5 I'm finding now that's not selling at price gouging levels, is UK based (no shipping to US) Fuchs and Ravenol --Starting to annoying me now... LOL I'm down this rabbit hole 3 + hours.



Keehn

Thread 'Maybe I'm blind, but can someone explain what the difference is between the BMW and MOPAR GL-5 differential fluids?'

I'm rapidly coming up on my initial 600 mile service, which I will be doing myself, so I'm doing the prep work in getting supplies ready.

But, I also know that BMW charges a premium simply for their marque (roundel), and industry standards are well...standards. So, when BMW's G3 axle oil says it's rated "API GL-5", then that means ANY manufacturer with a comparable product should also fit the bill, right?

Here's the issue. I've got ONE bottle of BMW's G3 oil (500ML) at $51.00 https://www.bobsbmw.com/store/product/bmw-synthetic-g3-hypoid-axle-oil-70w-80-500ml

But, doing some...
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"G3" sounds like a spec for a particular type of oil, but it is not.... so is nothing to do with a GL-3 spec. It just a name of their gear oil. The spec is GL-5.

My local BMW place uses 75w-90..... so do I now days.
 
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Even though I did the 600 mile service at BMW, I am planning to use Mobil1 15W-50 in the crankcase. I generally use a synthetic gear oil in the other two holes. Lucas brand is one I have used a great deal.
 
Then there's this that gives some reasoning.

When to use 80w-90 GL5:

  • If you live in a region with consistently high temperatures, a thicker 80w-90 oil may be necessary to maintain proper lubrication.

  • 70w-80 GL5 is thinner and will provide smoother shifting, especially in colder temperatures.
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I have a June 23 build Classic and in the manual BMW specifies
FUCHS Titan EG 4218 SAE 70W-80.

Not sure if you can get that but for me on the Fuchs website shows the following as a GL-5 oil but note the approvals include G3 BMW.

That oil is listed on the Motorworks site as around £17 a litre.
 

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Hmmm just to throw my 2¢ in ... I use Bel-Ray Gear Saver Hypoid Gear Oil 80W-90 and it has worked for me ... it says it is rated API GL-5 and seems to work good for me ...
 
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