So, I searched a crapload and some threads say that friction modifiers are needed and some say that friction modifiers are NOT needed for this diff...which is it?

I have the 3.76 LSD (Supra TT; Torsen type LSD). I currently have 75w90 Royal Purple Gear Lube in there and it seems to work OK but every once in a while I hear noises from the rear end...especially during slow turns (i.e. parking lots). The unit was brand new and I never changed out the initial fluids...I think I read somewhere that after the first 1000-2000 miles it should be changed out if the unit was brand new; perhaps to get rid of metal shavings and etc. So, I am changing some other fluids soon so i figured I would change the diff fluid as well.

What do you guys think? Thanks!

 

In the past, I used to change out the supra TT rear diff with royal purple or redline fluid. But I was once given two quarts of amsoil gear oil and changed it out in my car in which I felt a noticeable difference in noise. FWIW, I change out my rear diff fluid every 25k miles/2 year.

 

Did the noise get worse or better (quieter) with the Amsoil?

 

Sound Peformance known for building some of the fastest supras out there told me they run Valvoline synthetic 75w90 in their race car.

 

...cool. Well, on that note I see you too have the 3.76 LSD; what do you use, or have you used in the past?

 

The noise is definately quieter. But then again, I rarely hear anything behind the driver seat because I'm too busy enjoying the music from the turbos or Sc'd..

 

I listened to them and went with the Valvoline and as of now no noises or any issues. They told me that its not needed to run the $17/bottle royal purple unless you like wasting money. Now don't get me wrong cause I do use royal purple engine oil, but something so simple and mechanical as a torsen rear diff..I could see their reasoning.

 

I always have my radio on

and as far as the diff oil...money should be no object since you rarely change it out anyhow.

btw, walmart has 0w-30 fully synthetic motor oil.

 

I agree with Alexus 300. Amsoil FTW! I am getting ready to do my 60K and I will be switching over to all Amsoil fluids.

http://www.amsoil.com/company.aspx

http://www.amsoil.com/video/company/index.aspx

 

RP in my poopura rear end.
but I didn't pay for the RP .
No complains here.

 

Valvoline 75w90 with GM or Kendall LSD additive.

 

For those that don't know, Amsoil is one of the very few companies that I know of that makes a 75w-140 gear oil. There pricing is actually cheaper than Royal Purple if you get it through one of their dealer with a discount. I think I pay around $10/quart and if I purchase in large quantities, I get an additional 15% off which comes out to be pretty cheap.

 

this ok for oem rear ends? i no longer have my 3.76 installed, im back on the OEM gs430 diff

 

I thought no matter what you have to stick to 75w-90 diff fluid? What do these numbers actually mean? and is this a good weight for NY weather? (ranging from -5 to 100 degrees depending on the season)

 

From the factory, supra's require 80w-140 but it's hard to find it so amsoil is the closest thing. But on the stock non-lsd diff on 95% of GS out there, just go with the 75w-90 and you're set.