denut-L

iTrader: (11)

I have a question, I'm gonna be putting in a 01 gs300 diff into my 03 gs430 i've searched and came up with this

From jeffTsai
>>Ran into a few problems lol. Seems as if the drive shaft for the GS400 is slightly different than the GS300. The flange at the very end of the driveshaft that mates to the rear diff isn't the same size. The GS300 one is slightly smaller...only by like a few millimeters, but that's enough to prevent it from bolting up.

What will i have to do to make it fit? or can it fit at all? do you guys know anyone with this setup? would i be able to feel any difference at all in acceleration?

Thank you very much

Rock-a-Lex

iTrader: (4)

??? I thought that they are all the same; basically bolt right up. I KNOW CL member Lexizm has a GS430 (or GS400 - can't remember) that has the 3.92 open diff...which is from a GS300.

Frankdorn

iTrader: (7)

Trying to understand...

OK, so 400s and 430s have a 3.29, the 300s have the 3.92, and the Supra one everyone wants is a 3.76, right?

The 4XX guys can swap in a 300 pumpkin for supposed faster acceleration, but it does NOT have LSD, and gas mileage is slightly worse than with the Supra unit.

Am I understanding the big picture?

MDSC

iTrader: (3)

youre correct, with gs300 rear a gs400 or 430 is going to do nothing but spin from a stoplight

Alexus_300

iTrader: (4)

Lexizm has the GS300 ring gear mated to a supra TT LSD. He's not running a open diff.

JeffTsai

iTrader: (1)

You just need to swap over the companion flange. After that, torque the nut down and check preload torque on the flange. Once that's done, stake the nut and you're finished. Should only take about 5-10mins to do.

I have a quick DIY on my site www.ProjectGS.com/DIY
It's under Engine/Drivetrain first link in there for swapping differentials.

3UZFTE

You are correct, the only minor correction is that the 400/430 diff is 3.26, otherwise your above statement is all correct.

Denut-L, since your 430 rear end is already in there, why not just drop the 3.92 ring gear into the existing pumpkin, that way you don't have to deal with the companion flange. I actually have a GS300 diff sitting apart in my garage waiting for my LSD insert. Other than the companion flange, it's the exact same, I used a 3/8 impact gun on mine, and it worked fine.

denut-L

iTrader: (11)

Thanks JeffTsai for the diy info, you make it look easy
Anybody know what the torque spec is for the flange nut?

I'm afraid if i take apart the diff i'll never be able to get back together
I'll try swapping the diffs first and if i decide to install lsd later i'll hit you up for some diy info.

Thank you very much for all the info..I'll be on my way to pickup the diff now

Frankdorn

iTrader: (7)

Maybe this has already been covered in the archives, but is there a way to install LSD without swapping the pumpkin? I was told once the swap to a 3.76 diff didn't help acceleration all that much and gas mileage suffered by about 2-3. I was just wondering if there was an inexpensive insert or something to make it LSD...?

PS. Talking about a 400.

Rock-a-Lex

iTrader: (4)

...Really? He never mentioned that in his previous posts. Only mentioned that he has the 3.92 rear setup.

If you are right he MAY be the ONLY person that has mated the 3.92 gears (from the GS300) into the Supra TT LSD rear and installed it all into the V8 Lexus GS.

...interesting

Alexus_300

iTrader: (4)

The internal of the Supra TT diff. is very much the same as the GS300/GS4. I've seen a few people who have mated the TRD LSD with the GS300 ring gear for better acceleration. But gas milage will suck big time.

denut-L

iTrader: (11)

This is to JeffTsai what kind of 35mm socket did you use to get the flange nut out? From your diy page it looked like you had a great neck, was it a standerd socket or axle socket?

I could only find a 35mm deep socket for the axles and it would not fit all the way down cause it's too big. only 1/4 of the way down

I went to sears and they only had 32 n 36mm

Please lmk as i'm stuck on this.

Thank you

Rock-a-Lex

iTrader: (4)

Wait, your combining two sets of separate thoughts...

"The internal of the Supra TT diff. is very much the same as the GS300/GS4."

I don't see how it is that similar to the stock GS diffs because the Supra TT diff utilizes a Torsen style LSD inside. It functions completely different.

"I've seen a few people who have mated the TRD LSD with the GS300 ring gear for better acceleration."

I have seen this too but be advised, a TRD LSD is NOT a torsen style LSD! I too researched this option of just throwing this part into my stock GS400 open diff because it worked great and was cheaper but the install was more costly and wound up being close to the same as just buying a complete Supra TT LSD unit (for an added benefit the Supra TT LSD came with shorter gears). Oh and the drop in TRD LSD unit does NOT add acceleration at all! It simply allows you to put more even power down to the ground and if you only have a stock GS300...it is a rather pointless addition.

JeffTsai

iTrader: (1)

I got mine at autozone for like $10 or so. I don't think it was specifically for an axle.

The torque on the nut is 249ft/lb or less. It can vary because you need to set it accordinly to preload on the flange. On a new bearing the preload is 8.7-13.9in/lb, on a used bearing it should be 4.3-6.9in/lb.

Alexus_300

iTrader: (4)

Let me clarify this a little better for you. You are right when you stated that the LSD in the MKIV Supra TT auto is a torsen. This is essentially a gear driven/engagement form of torque application. The TRD unit on the other hand is a clutch type LSD where it uses clutch plates to transfer the load to the wheels evenly. Therefore, that's why friction modifiers are needed on the TRD LSD so that it doesn't clunk and make noises. For the majority of the people on this board who has a GS, they will never make enough power to break the torsen unit that's why the MKIV auto diffs. are great alternative. As far as LSD is concern, it doesn't matter which LSD you use, the gearing is what gives you faster acceleration off the line not the LSD unit itself. The drawback is that the revs will be much higher on the hwy. so gas milage will drop by 2-3 mpg. Hope this helps.