Quaife LSD - Motul 75w90 or 75w140
I have purchased a Quaife LSD for my C63 w204, it's now on the way from UK to Shanghai. It's my first mod on the car to increase its performance.
I'm wondering about the oil for this LSD Diff: Motul Gear 300 (75w90) or Motul Gear Competition (75w140)?
I use the car daily and also on trackdays on 2 tracks here in Shanghai. I just bought this car 2nd hand recently, and took it once to the track. I'm planning to track it regularly, maybe once a month.
I saw in previous threads dealing with LSD that some of you already used both or them, i'm wondering what was you decision factor and what is your actual feedback?
Thanks for your advices

here my check-in: https://mbworld.org/forums/new-membe...-shanghai.html




Example: https://mbworld.org/forums/c63-amg-w...san-diego.html
Is ACG wrong?
A few also run the Castrol Syntrax 75w140 and I haven't heard of any blowing up.
Edit: I did a Google search and turned up a lot of 75w90 being used as well. Seems to be quite the debate. Quaife does not list anything on their site, just to use the manufacturer recommended gear oil. But the consensus on the intertubes looks like 75w90 is the winner. So I stand corrected.
Last edited by BLKROKT; Feb 11, 2017 at 03:43 AM.
Your new Wavetrac® differential is incredibly durable and will withstand the harshest environments...as long as suitable oil is used. Many customers ask what oil we recommend for use with the Wavetrac® differential. We feel the best answer is:
Some have friction modifiers designed for limited slip differentials. These modifiers generally increase slipperiness and are intended to reduce clutch disc chatter in conventional clutch-type LSDs. Some gear oils such as Red Line Oil's Shockproof® type have microscopic solid particles in immersion in order to "cushion" transmission components, acting as an extreme pressure agent. The Wavetrac® and all helical gear differentials in general, operate using friction. The friction generated between its internal gears and its housing are what allow this type of differential to function.
Gear oil additives that drastically reduce friction will actually reduce the performance of gear differentials. The internals of the diff get too slick to generate adequate friction - reducing the differential's effectiveness - reducing its ability to drive both wheels.
In conclusion, when using a Wavetrac®:
- Use factory spec oils for your car
- Use Motul Synthetic high performance oils if you wish to upgrade the oil. Please consult Autotech Driveline for recommendations.
- Avoid gear oils with limited slip additives.
- Do NOT use RedLine, Shockproof® or similar gear oils.
Performance Gear Oils we recommend: Requirement Oil 75W90 Motul Gear 300 (100118 1l) 75W140 Motul Gear Competition (101161 1l) Motul Gear Oil is available from Wavetrac dealers
They suggest the Motul 75w90, or any other similar oil that fits the OEM spec (open diff, not the OEM LSD with clutch system). They also noted that they cannot recommend the Motul 75w140 as they are not sure if it includes a modifier for clutch.
I found the Motul specs, they are attached.
Even if I plan to go to trackdays frequently, the car is mostly used on the streets. I will then probably stick to their recommendation.
Thanks for your inputs
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I don't think they have any gear oils with friction modifiers for clutch type diffs.
EDIT: https://www.motul.com/my/en/news/gea...-gear-changing
Last edited by Jasonoff; Feb 11, 2017 at 09:22 PM.
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From the PDF linked above: "Included friction modifier avoid noisy or dragging limited slip differential."
That and the fact wavetrac recommends the 75W140 but explicitly says "Avoid gear oils with limited slip additives" lol.




Plan to install it this sunday morning and directly go to track it sunday afternoon on the SIC (Shanghai International Circuit). I'm really looking forward with excitement for this day: will be the first time for me on this nice track and testing the LSD.
I will roast my tires as they are near to the wear marks. lol
Plan to install it this sunday morning and directly go to track it sunday afternoon on the SIC (Shanghai International Circuit). I'm really looking forward with excitement for this day: will be the first time for me on this nice track and testing the LSD.
I will roast my tires as they are near to the wear marks. lol
This sunday I went to the shop to get the Quaife installed, and after they open the diff, a Quaife was already inside! looks like an older type compared to the new that i just got (the ring has no wave). But anyway it's fine to me, so I just kept the actual setting and I will sell the new one.
Regarding the oil, I ended up with AMS severe gear 75w90 as the Motul was out of stock at the official dealer.
Went to the track and destroyed the rear tires and the brake pads. Great car on the Shanghai International Circuit, lot of fun! Changed the old Pirelli P zero rosso against Yokohama AD-08R and noticed great improvement regarding the stability of the car on the track








