It's probably the gears on the LSD. I heard them a little when I first installed mine using Toyota fluid + LSD additive. Once I switched to Redline fluid it went away.

Make sure they used fluid with a Friction modifier for LSD... sure they did, but its worth asking.

 

Hi Dave, can you please be more specific as to exactly what fluid (make, viscosity etc), is required for this Supra TT 3.76 gear LSD install? I will be doing this same mod as soon as my car comes out of storage (2 -3 weeks) and I want to make sure I do it right. Thanks!

 

Mine is the TRD Clutch Type LSD like Fireball put in, so I can't speak to the right stuff for the 3.76. I believe I used Redline 75W90 gear oil in mine, but I'd recommend doing a search for what might be different on a Torsen 3.76 unit. It may not even need the friction modifiers.

 

Yeah, Dave's right. The clutch type LSD (TRD) needs a different kind of gear oil than the Torsen. Your best bet might be to check the Supra forums and see what the TT guys there are using with success.

 

Actually it's the same weight. I put Mobil-1 synthetic gear lubricant 75W90 in my Supra diff. Any auto shop has it.

 

When you say you stalled it up to 2800 and let off, do you mean you held the brake while revving it up!? I wouldn't do that (very hard on tranny), plus you don't need to.

Anyway, glad you like the mods and that the delay was only for exhaust gaskets!

 

Just curious to know why this is different from what the TC does. I am guessing the TC does not achieve the same stall speed as doing it manually by keeping one foot on the brake and revving the engine to 2800 rpm before letting the brakes go.

I am interested in a technical explanation.

 

Bit, so you're saying that the formulation of the gear lube for both types of LSD is the same(i.e. not just the viscosity)?
I've always understood them to require two different types of lube. Ya learn something new every day I guess

 

I think Bit only said part of what needed to be said... the weight of the lube is the same for both clutch and torsen type limited slip differentials. The clutch type must have an LSD friction modifier in the fluid either built in or as an additive (sold both ways) or something bad happens (don't know what that is... either it slips, tears gears off or it simply doesn't work as designed).

My understanding from reading online here is that the Torsen type does not need the friction modifier. I don't know if it'll hurt it, but if I had one I wouldn't use it.

 

That's basically my understanding too Dave. As I remember in my off-roading days, you had to be aware of the specific type of gear lube you were using because there were a variety of limited slip diffs (i.e. gear driven, clutch/cone type etc.) and lockers. Some types of LSDs were more sensitive to the lube it needed than others it seems to me...

 

I went through 3 different lubes in a two week period before I ended up with what was recommended for my particular ATS Carbon LSD. You guessed it, the special ATS gear lube. Had serious d^mn problems with the other lubes [excessive noise, vibration, grinding, etc].

 

Now imagine a 4000rpm stall converter and a TRD LSD for my V300 ...

Can we say WHOA?

 

jtan, 4000rpm stall, are you serious? Your car must DRINK gas.

 

Well I'm the reason why RedGS4 has second thoughts. Our cars dyno'd very close in HP & Torque*, and we have very similar engine / drivetrain mods.

The biggest mechanical difference between our cars is that Redgs4 is running a stock gear ratio and I am running 3.76. I am consistently 1 to 2 tenths quicker in the 1/4 mile**. One run RedGS4 had a holeshot on me by almost a car length off the line. (Basically I had a poor reaction time on that run) I thought that he would win for sure, but not only did I continue to catch up to him, but continued to pull away all the way through the traps.

We have pretty much come to the conclusion that my gearing has not only allowed for quicker 0-60's, but I am also higher in the power band through the gears all the way through the quarter mile.

IMO, unless you plan on racing someone past 135mph***, the 3.76 is the way to go for a NA car from 0 to 135.


* Reference this thread: https://www.clublexus.com/forums/sho...hreadid=112066

** Note: We ran our cars on a tune & test day, which means reaction times are not factored in to our ET's. In other words, you could sit at the line for 10 seconds after going green and still run a good ET, because the clock won't start till you leave the line. This is an interesting scenario, where you can run an ET faster than the other guy by several seconds and still lose the race.

*** Note: I have tested and verified the 135mph governor several times to validate this top speed. Rominl was with me riding shot gun as my witness.

 

that's why i will get the rmm unit too. i don't race people at 135mph, but i want to eat them at the light