Sounds like its time for a new diff to me. We deal directly with OS Giken and Motul and run both their products in all of our race cars and mostly any car that comes through the door for a drivetrain upgrade. If you guys are interested I could set up a package deal with OS Giken and Motul Gear oil. Feel free to PM me for some exclusive pricing.

 

What fluid? I have to change the fluid on my NISMO LSD quite regularly or it starts to make a lot of noise and is generally unhappy.

Gotcha - I feared you were spinning a lousy or bald tire.

I do like my NISMO diff minus the fluid changing, however, I've never driven the OSG.

 

I too have heard you should only use the OS Giken fluid in their diffs, it is expensive for diff fluid but I rather the diff last me 3-4 race seasons than risk something going wrong with another fluid.

 

You can use other fluids like Motul 90PA, Redline 80W-140, or any AGMA Grade 5EP oil.

 

OSG recommends their super heavy fluid officially. But when we speak to their technical department on the phone, they acknowledge that many other fluids work just fine. We have used the OSG as well as Motul Gear 300 75/140 with equal results. The nice thing about OSG is if something ever breaks, they want to know about it and it most cases they will repair often at no charge. They design their stuff to be nearly indestructable under true race conditions provided that normal maintenance is carried out.

Let us know how you like it. FYI, we have not had to re-shim an OSG yet. So it's highly unlikely you will need after-market shims. But definitely order a new set of side bearings.

 

Amsoil 85w140 severe gear

 

The Motul 90PA I've been using needs to be changed more frequently than I think is reasonable before it starts to make noise and is generally unhappy.

I'll have to try that next - thanks.

 

You did! With my car.

 

I've been looking at the Quaife LSD, which I've been quoted less than $1K shipped from a vendor here. It doesn't require rebuilds or as frequent fluid changes since it's not a clutch type. What are the disadvantages of the Quaife compared to the OS Giken? My car is my year round DD, with 1 or 2 autocross events per month during the season.

 

I have the Quaife on my base model Z. I have been daily driving it for 2 years now, and autocross about twice a month. Maintenance is low, as I only change the differential fluid every 15,000 miles, and wheel spin is non-existent as long as I keep the inside wheel from going airborne.