DrewGS4

For those of you with 3.76 LSD or TRD LSD which kind of synthetic rear differential fluid are you using or can recommend.
There are so many on the market with all different grades

For example:
mobile 1
Castrol GTX Gear Oil 75W90
Valvoline
Royal Purple MAXGEAR 75W90
Amsoil
Redline 75w90 which has the additive and 75w90s no additive or 80w140

gets very confusing on which one to choose and in which grade with or without LSD additives, etc. .... Any recommendations?

Hameed

I kept mine simple. I just put in the recommended Toyota LSD differential fluid. This fluid is specifically for this LSD and is used in Supras.

rominl

iTrader: (4)

i use redline 75w90, NOT the 75w90NS

redgs4

If your LSD requires the additive make sure to use a diff oil that includes it. Things get ugly quick without. [Personal Experience ]

bitkahuna

iTrader: (20)

I used Mobil-1 synthetic gear oil 75W90 I believe.

FutureGS400

I am using Mobil1 synthetic in mine.
The TRD would use a different type because it is a different type of LSD and requires a specific formulation to work correctly.

DrewGS4

Thanks guys for the information. I checked over on the supra forums and most of the guys are running amsoil or redline oil.

Hameed....i only use OEM toyota fluid for my transmission and the red toyota coolant. No substituting those fluids with anything synthetic or generic versions. But with engine oil and rear differential people say that synthetic is better for optimal performance.

I guess you can never go wrong with mobile 1. I am leaning more towards royal purple or valvoline.
I think the main thing is that you change the oil out frequently since it only takes 1.5 quarts on the supra LSD. The gears churn and churn so fast which is only being lubricated by 1.5 quarts which results in the oil getting dirtier and burnt quicker.

FutureGS400

Personally, I don't believe there is any real need to change the gear lube in the rear end frequently. It shouldn't get dirty and burnt (as you suggested) IMO- unless there is something wrong.
The rear diff. is not like your engine oil where it is subject to extreme temps, combustion contamination etc.
I guess under extreme conditions (i.e. racing) it might be a good idea to change it more frequently...
I could be wrong on this; have to check into the issue more.

rominl

iTrader: (4)

i agree, i don't see any resaon to change the rear end fluid often unless you track your car very often and put the lsd into very good use. otherwise i think doing it every 30k would be enough

grnstreak

I don't recommend using synthetic oil in a clutch type LSD. Synthetic is too slippery for the friction surfaces.

rominl

iTrader: (4)

well some synthetic fluid they have friction addition to create the necessary friction for clutch type lsd. i think those should be ok?

FutureGS400

Or you could just add about 2 cups of sand to the diff... plenty of friction now

DrewGS4

LOL..... In the end I decided to go with the Redline synthetic 75w90 It already has the additive for additional protection for LSD. So far very happy.

FutureGS400

Redline makes good products IMO, I've used some of their stuff over the years..
The friction additives are only for LSDs using the clutch/cone type of mechanism (e.g. TRD ). Not necessary for the Torsen (gear type LSD) as far as I know. Probably doesn't hurt anything, just not needed.

DaveGS4

iTrader: (2)

Thats why Redline adds a friction modifier to their synthetic LSD. Like Future says, I've read its not needed for the Torsen variety though.

I've used the Redline in my TRD LSD for a couple of years. definitely good stuff. Also use their water wetter product.