OS Giken Diff Oil Choices
 

Ok, yes this another oil thread, but one that I have not been able to find any info on from a reliable source. I have the OS Giken clutch LSD in my 370. The oil OS Giken recommends, OS-250R is 47-57 dollars / liter (~1.1Qt).. It is an 80w250 oil.

Redline makes this thing called Heavy Shockproof which is a 75w250 gear oil that is less than half the price of the OS-250R oil. With having to change my diff oil every 2 track days this could save some money down the road.

When I talked to OS Giken before they said that you could run the Redline 75w140 (no friction modifier) in there but they would recommend the OS-250R. So I am thinking the 80w250 Heavy Shockproof should be good.

Has anyone run this oil (or something else) in their OS Giken Diff or have actual factual information regarding this?

OS Giken is closed today already tried earlier.

I had a Kaaz in my 240. But I use to run MObie 1 oil with a friction modifier.

If OS is saying to run another type of oil, do it. I'd check your oil after one race day. Just to be on the safe side

Use only the OS Giken oil, it is widely known not to use any other unless its emergency of some sort, i say wait till they open or buy from different sources.

People who have previously tried it (try my350z because the diff is the same) have reported additional NVH and clunking from the clutch. However you care about performance and I can't say that I can recall anyone ever saying whether it was up to the task or not. Sorry it's not much help.

I ran my OSG for three years with couple thousand miles of track use with only OSG fluid and I highly recommend it. No issue or noise, ever. Then I knew of a guy that ran a different quality oil ( I believe Redline) but he have to change after every track use and his OSG was periodically popping and grinding. I changed mine every three track weekends. But for street use it can go about 10-15K miles I believe. I always use half the recommended time frames for my personal preference.

^this

Osgiken is one of those companies where all they focus on is a single application (clutches). I'd trust them to know what's best for their products. Normally not an advocate for blind faith but they've had a proven track record for years now.

Ok thanks, good input guys. I'll stick with the OS Giken Fluid.

I still plan on calling them to specifically ask about the Redline 80w250 though just to see what they say. I'll post an update.

Alright, just got off the phone with OSG.

They said testing has shown the Redline line of fluids to cause accelerated wear to the clutches and require a more frequent change interval. Whereas the Motul Gear ff Competition 75w140 oil has shown to be a better performer more comparable to their own fluid the OS-250R.
With the OS-250R oil in use, they recommend an OEM oil change interval of around 15K street mi. or every 8 track days.

75W90 Redline for transaxel gears
OS-250R for diff or equal.