lexoman

i purchaced a 99 gs400 last oct 2002 with some mods rmm full kit,front strut brace,lower front
brace,do gs 400 come with trd shocks? rmm intake,rmm exhaust,how can i tell if i have lsd. can i tell by power braking if i have a lsd? please help.

BananaGS

there is NO know test that I can tell, have to open the diff out and look

LexCiting

Actually you can test it. The best way to test it is to get your car on a lift. Basically, put your car on a lift, put it into netural, turn your right back wheel by hand. If both wheels move, you have a LSD installed.

BananaGS

you mean both wheel more in the same direction right? because I have the open NON-LSD and both wheel move in different dirrection when the car is on the lift, and I move 1 wheel. Both stock diff and supra 3.76 gear does this.

skier1

I agree with BananaGS. I recently put the Supra TT auto differential in my GS4. I did open the back cover before I put it in to verify that it had the LSD. It did. Once I got it installed, I noticed as I was tightening up the half-shaft bolts and spun the wheel on the side I was working on, the opposite wheel spun in the opposite direction. Now when I get in it hard around a corner, both tires spin and the rear kicks out a bit

That's a nice feeling.


BTW BananaGS, did you ever find another rearend with and LSD unit?

oldguy

get your car stopped on sand or gravel. stop. floor it. did you leave one or two tracks?

lexoman

i have done that before and i remember leaving two deep tracks.

BananaGS

2 tracks, so is mine diff, but I had opened out, it does not have LSD gear

LexCiting

BananaGS - yes, both wheels should move in the same direction. Thats the key. Both tires have to move in the same direction. When I had my car at SRT for my 60K service (prior to the TRD LSD install), I turned my right rim by hand, and the right right would move but there wasn't any movement from left tire, in terms of moving with the right tire. After having the LSD installed, I could "feel" something lock as I moved the right tire, and the left started moving in the same direction. I thought the supra 3.76 unit was a LSD?

BananaGS

LexCiting,


"I turned my right rim by hand, and the right right would move but there wasn't any movement from left tire"
That is totally weird, I am looking at my stock diff now, and the open-diff supra 3.76, if I turn the wheel on one side, the other side will move in opposite direction, NOT SAME direction, but It WILL move for sure.

Maybe be the key thing we are missing here is the drive axe should be locked??? then and only then on side will move? if you have an open diff . or SAME DIRECTION MOVING? I looked at the open diff gears design, there is no way if you mve one side and the other side won't move, since the gears are connected, but I did not tried to stop the drive shaft while moving the wheel, that would be interesting, but your car will roll down the hill then when you are in park HA HA HA.

====================================
Supra TT 3.76 Auto : year 93.5-96 has LSD from factory
Supra TT 3.76 Auto : year 97+ has NO LSD from factory, not even optional, (I know that now) I have the 97 diff.

I am not 100% sure, but many supra guys said that their 97+ diff FOOLED them also at the track, they think Toyota had modified the OPEN DIFF so that it work a bit like LSD gear, but without using TORSEN OR CLUTCH in the 97+ production.

Personally, I don't see how they do it, but I know for "sure" that I get better traction with this open gear supra for some unknow reason? I am still pondering. My VSC has not kicked in once since my install, I know the traction light is blinking in hard turn, but the car just does not slide out of control like before anymore, maybe my VSC does not work anymore, HOw can I tell, there is NO check engine light?, now, I am worried at the same time felt great around the correr .

Maybe the ADDED torque make me a BETTER driver, perfect condition for the NA GS? what do you think? I am sure you know this first hand since you have the blower under the hood... hee hee
I drove through water and accel around the corner, my rear end is sliding, traction light is blinking, but the VSC is NOT kicking in , I just keep the same or bit less pressure on the gas pedal, and the car just correct itself, What the heck? I know I've done that samething before at the same corner and my VSC was beeping like crazy and when the VSC is activated, my back end will be snap back in place at the same time the engine is power down to deaccelerate. Now, I just feel the rear end sliding,then it just stop sliding, while the car keep moving forward, No snap back effect or VSC beep. The service manual said that the traction ECU will trigger check engine light if it does not work.

LexCiting

BananaGS - In the first part of my post I said :
You paraphrased my post, but left out the important part:

When I said no movement, I meant no movement in terms of the direction I was turning my right tire. "With" meaning in the same direction, as opposed to "against", which would mean in the opposite direction.

Didn't mean to confuse you, or anyone else out there. LOL

The answer to lexoman's questions is YES, you can test it. The best way outside of opening up the unit is to lift the car up, put it in netural, and turn the right wheel in a forward direction, see if the left wheel locks, and starts moving as your turn the right wheel.

jeffandi

With a clutch type (TRD) differential, both wheels will spin in the same direction when you do the test described earlier. With a torsen type (Supra LSD) differential, the test will result in the same behavior as an open differential (stock GS), one wheel spins in the opposite direction of the other.
There is no way to test for a torsen type LSD except to open the pumpkin and look inside. Pictures of a torsen LSD have been posted on the board here. Key thing to look for is a worm gear in the LSD as this is the foundation for the torsen type LSD.

I bought my Supra diff. froma guy off a 97 TT auto Supra. I didn't open the pumpkin so I don't know for sure whether I have the LSD or not. But like BananaGS has said, I do notice an increase in rear traction.

Jeff

///MDex

See the Application of the TORSEN Diff on the manufacturer's website here

LINK

1996 Supra Contained a TYPE 2 TORSEN Diff., the same that is in a 1998 IS3

TYPE 2 SPEC



HTH

LexCiting

Dex/Jeffandi - Great points made. I can only speak on the TRD LSD since that is the one installed on my car.

tomtnc

I've summarized all of the MKIV Supra differential specs and applications below:

Open 4.272 Ratio (11 teeth pinion, 47 teeth ring): Standard differential for 93-96 normally aspirated automatic and manual transmission Supras.

Worm-gear Torsen-type LSD, 4.272 Ratio: Optional differential for 93-96 normally aspirated automatic and manual transmission Supras.

Worm-gear Torsen-type LSD, 3.769 Ratio (13 teeth pinion, 49 teeth ring): Standard differential for 93-96 TT automatic transmission Supras.

Worm-gear Torsen-type LSD, 3.133 Ratio (15 teeth pinion, 47 teeth ring): Standard differential for 93-98 TT manual transmission Supras.

Open 3.769 Ratio: Standard differential for 97-98 TT automatic transmission Supras.

Helical-gear Torsen-type LSD, 3.769 Ratio: Optional differential for 97-98 automatic transmission Supras.

Open 4.083 Ratio (12 teeth pinion, 49 teeth ring):: Standard differential for 97-98 normally aspirated manual and automatic transmission Supras.

Helical-gear Torsen-type LSD, 4.083 Ratio:: Optional differential for 97-98 normally aspriated manual and automatic transmission Supras.