Do they make Mobil 1 75w140 in a non Limited Slip formula or are you guys putting the LS version in? The diff on the AP1 and AP2's are the same, right? So I can run whatever diff fluids people are talking about without worrying if they are talking about ap1 or ap2? I have a track day coming up on Sunday and need to change out my diff fluid so locally available fluid this time around is a necessity. Then I'll change over to Amsoil (I use their SS motor oil now).

Thanks.

 

Ive been using redline. Good stuff.

 

another faithful Amsoil fan here, 75w-140! with tons of autos and hard launches with RS3's on concrete.

 

Mobile 1 only comes in the LS labeled version.


Synthetic Gear Lubes Mobil 1 Synthetic Gear Lubes are designed to help protect and extend the life of automotive gears, rear axles and differentials. They provide outstanding protection, even in the most extreme operating conditions or service, and exceed the most severe requirements for many automobile and truck rear axles.

Available as:

Mobil 1 Synthetic Gear Lube LS 75W-140

Features & Potential Benefits

Mobil 1 Synthetic Gear Lube LS 75W-140 is a premium performance, synthetic, multi-purpose, automotive gear lubricant designed to meet the highest level performance requirements of many modern passenger vehicles in all types of operating conditions including limited slip applications, as well as deliver outstanding power transfer performance. Compared to conventional hypoid gear lubricants, Mobil 1 Synthetic Gear Lube LS 75W-140 performs exceptionally over a wide range of temperatures.

Mobil 1 Synthetic Gear Lube LS 75W-140 achieves this through a unique proprietary combination of synthetic base oils and a unique additive system, including the SuperSyn anti-wear system, that deliver optimized viscosity-temperature properties together with the highest level of inherent formulation stability and protects against thermal and oxidative degradation, wear and corrosion, and viscosity loss associated with premature shearing.

Mobil 1 Synthetic Gear Lube 75W-140 LS contains special friction modifiers designed for limited slip-type differentials. In most applications, the addition of special LS (limited slip) additives is not required. For axles requiring the highest level of limited-slip performance, OEM specific LS additives can be added to this fluid. (emphasis added)

For more information, see the Mobil 1 Synthetic Gear Lubricant LS 75W-140 Product Data Sheet and Material Safety Data Sheet.


Mobil 1 Synthetic Gear Lube LS 75W-90

 

This was casually mentioned above, but I wanted to restate: If you are buying Amsoil, the only 75w140 they offer is called "AMSOIL Severe Gear (TM) SAE 75W-140". Retail is $20.95/qt at my local Amsoil peddler.

 

Its been about 4 years now since switching to 75/140. Previously had a lot of diff noise and harsh feel with the lighter Honda 90w, I thought my diff was about to blow. It immediately was apparent this took care of the diff wining and rough operation and will never go back. I just use the standard Castrol 75/140 gear lube off the shelf at the local parts store.

 

I started using Motul 75w-140 every since I got my rear diff from S2KPUDDYDAD as per his recommendation. Actually he suggested Amsoil 75w-140 but i like Motul more.

 

I find it wiward that people stick to the SAE90 that Honda recomended back in 2000, or even thicker. Further more, Mazda recomends 75W-90 for their RX8 diff, which is using very similar internals with the S2000 as we all know. I use Castrol Syntrax Longlife 75W-90 GL-5, if it is good enough to have the approval of ZF for the BMW diffs, i am sure it's good enough for our diff too.

 

It's been a long time since I looked at the numbers, but I think the old 90 SAE rating covered a range of something like ~75-110 IIRC (I could be off on the exact numbers). So to me it's safer to used a range higher than 75W-90. I put in Amsoil severe gear 75W-110 recently. No problems so far but I haven't driven the car hard yet.

 

Ι see this a bit different, if Mazda, which manufactures the hypoid gears for the diff, and BMW, recomend a 75W-90 for the diff, there's no reason it isn't suitable for an S2000. I give special attention to the Mazda recomendation, as it's also using a torsen/helical rear diff, and hypoid gears very similar to ours.