fireball

i changed the diff fluid last week end b4 i realised that there are 2 mobil1 75w-90 synthetic gear lubricants available !!
i used the black bottle on the right b4 i knew that there was another one ... been driving around with it for a few days... please tell me i didnt use the wrong one

fireball

this is my diff oil change from last weekend

http://forums.s2ki.com/forums/showthread.p...threadid=203268

topcat7111

It the same 75w90 gear oil, just different packaging.

fireball

i rang the mobil lube helpline for an answer

the one on the left is for diffs with lsd
the one on the right isnt !

doh i put the wrong stuff on lastwkend

time for another diff fluid change

paivag

So which do we use on our S??? Silver bottle or Black one??

fireball

silver bottle !

paivag

THX!

Road Rage

Not so fast, fireball.

I would agree with you if the S2000 used a conventional LSD that has clutches, since the coefficient of friction determines how the clutches engage and disengage, and whether one experiences "chattering" or "grabbing", and by what % of lockup the LSD provides, wheel to wheel.

So the silver likely has some friction modifier in it, while the black doesn't. The black is likely targeted for the racing market, since they would either want no COF modifier, or would want to be able to add just the right amount to get the performance they need. This would especially be true for auto-x'ers.

Once again, the US seems to get short-changed by the biggies (Catrol, Mobil) in that they offer a greater variety of lubricants to the rest of the world. We get "one size fits all". (Oh, before I get flamed by the guy in the Aussie Forum, I do understand that S2000's cost a lot more in Australia than in the USA).

But Torsen LSD's do not use clutches, so the COF is irrelevant, hence it would not seem to matter which one to use. I am guessing the black is more costly - is that right?

However, if warranty coverage were the main concern, I would stick to whatever the dealer or mfr recommends - if the dealer says 75w90 is OK, get it in writing. Otherwise, it might be prudent to stay with a 90w or the 80w90 recommendation.

Since it doesn't hget that cold down under (does it?), I would stick with the single-weight or the lube with the narrowest vis gap, which is 80w90.

But in the end it is your choice, of course.

fireball

the black bottle costs $13au per 1L bottle
the silver one costs $17au !

Road Rage

Now that is odd! That friction modifier must have been powdered platinum!

Either one would be fine for your car - I certainly would not re-do it just from the mfr's recommendation for the reasons I detailed.

Thx for the info - maybe Mobil's marketing plan in the uS makes sense - people are already confused here.