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This is more like it.
Notice the distance between the centerline of the pinion and the center of the ring?
That's the offset and the more the more the hypoid shaped teeth slide over eachother, almost like a worm gear set.
@ Rolan Thunder. Clutch disc, Friction Disc, Washer, how ever you call them, they are there. And to me they are very similar in form and function to a motorcycle clutch.
And in a motorcycle, the type of oil used could make a huge difference. Use the wrong oil and the clutch slips....
@ All: So, i am still puzzled what a difference a LS gear oil could make and if it is safe to use it in the S2000 Differential?
It is mentioned here in the thread that sometiems the tabs of the clutch or friction discs are sheared off and come out the next fluid change.
Could this be caused by using a LS Diff fluid, creating to much friction on the clutch or friction disc and cause them to shear off?
Here is clutch type differential what requires LS diff fluid (normal diff fluid with friction modifier):
Clutch plates require friction modifier for smooth action.
Differential on our cars is Torsen type-2. The locking action is mainly generated by friction between gears and diff case (this is explained on workshop manual). Yes there is clutch plates also, but their role is pretty small compared to gears.
Is the friction modifier needed in torsen?
Answer: In a helical gear diff, however, the stick-slip tends to show up as an audible noise, described by some as a “rusty screw” noise, or as a squeak or moan. You tend to hear it in very low-speed turns, when the steering is at or near full-lock. So, you might hear it while maneuvering in a parking lot, or turning the car around in your driveway. This noise is, as I said, just a characteristic of the friction properties, and is normal. But, if you hear it a lot and it annoys you, adding a few ounces of friction modifier to the axle lubricant will almost always eliminate it. So, the bottom line is it’s up to you.
Source: https://torsen.com/tbr-lube-friction-modifier/
Finding lots of GL5 hypoid gear oils as well as notes going back to at least 2002 that GL6 spec is obsolete in that GL5 does everything it did.
Amsoil has a flexible "Easy Pouch Bag" GL5 in 75W-90 and 75W-140 grades. Looks handier than those messy little pumps needed for the rigid bottles. 75W-110 which may be the most appropriate only comes in rigid bottles.
The data sheet for LE-1605 I just downloaded shows it as a GL5 oil, but the sheet is dated 09-14. Also rated as MIL-L-210SE. Looking for a more recent sheet at present. Royal Purple, Red Line and others, of course have GL5 lubricants so we're back to the inevitable What's best?" question.
Here is clutch type differential what requires LS diff fluid (normal diff fluid with friction modifier): https://www.youtube.com/watch?v=WeLm7wHvdxQ
Clutch plates require friction modifier for smooth action.
Differential on our cars is Torsen type-2. The locking action is mainly generated by friction between gears and diff case (this is explained on workshop manual). Yes there is clutch plates also, but their role is pretty small compared to gears.
Is the friction modifier needed in torsen?
Answer: In a helical gear diff, however, the stick-slip tends to show up as an audible noise, described by some as a “rusty screw” noise, or as a squeak or moan. You tend to hear it in very low-speed turns, when the steering is at or near full-lock. So, you might hear it while maneuvering in a parking lot, or turning the car around in your driveway. This noise is, as I said, just a characteristic of the friction properties, and is normal. But, if you hear it a lot and it annoys you, adding a few ounces of friction modifier to the axle lubricant will almost always eliminate it. So, the bottom line is it’s up to you.
Source: https://torsen.com/tbr-lube-friction-modifier/
Point is the recommended viscosity is a 1999 spec single grade SAE 90 GL5/6.
If one could go to any automotive store today and still get exactly that, there would be no discussion (or less...)
So one has to translate '1999 spec single grade SAE 90 GL5/6' into 2018 gear oil.
Unfortunately Google Translate does not work for this.
The most acurate translation in my opinion is SAE 110, 75W110 or 75W140.
Because of the GL6 in the original the modern 75W90 oils are out.
Why are GL5 oils (especially the 75w-90 is in the ball park) out as they appear to be modern lubricants? Still sold.
"Essentially, the heavier, thicker, or more viscous that the oil is, the better it lubricates (generally). It leaves a heavier film adhered to the surfaces being lubricated. This reduces friction. But, that means that a differential operating in 75W-140 oil will have fractionally less locking effect than the same unit operating in 75W-90. This difference is not night and day – the changes are subtle. But if you’re fine-tuning a race car, it does offer one more knob that you can turn. By the same token, lubricant formulation and additives used have a similar bearing on the matter."
My S loves the thicker diff fluid and I have gone 60k miles once just to see if I'd get any metal fuzz on the magnet, I didn't. So now I change it out every 6 oil changes(45k miles). If you don't want to run the 75/140 you can do a 50/50 mix of M1 75/90 and M1 75/140. That would be like a 75/110.
Reading both parts puts this in good perspective. Higher grade reduces friction and consequently reduces the limited slip function of the differential by a, perhaps, insignificant factor. Torsen's "house oil" is Chevron Supreme LS 80W90. Yep, a LS oil.
Extract from the API website (emphasis added)::
GL-5 Active The designation API GL-5 denotes lubricants intended for gears, particularly hypoid (see note) gears, in axles operating under various combinations of high-speed/shock load and low-speed/high-torque conditions.
GL-6 Inactive The designation API GL-6 denotes lubricants intended for gears designed with a very high pinion offset. Such designs typically require protection from gear scoring in excess of that provided by API GL-5 gear oils.
With the Honda spec being GL-5 or GL-6 the GL-5 is certainly good enough.
I did read the thread and remember reading prior to this time. It can be difficult to deduce a direct causal factor for the "ears" being magnetically captured to the oil used. It could be everything from how the driver was driving to manufacturing qualities. Billman who authored #27 has clearly stated that Mobil1 75W 90 has, in his broad experience, been trouble free. Mobil1 75w90 a GL5 and better, appears to meet the Honda requirements and then some. I sleep well at night, but thanks for the input. Tot ziens!
09-14-2018, 09:24 AM
