TomWahjudi

All,

I need to find the ratio final drive ratio on my LS400, build date 02/95. Is this something I can find on the car pasted somewhere ? Any other leads ?

The reason is because I'm thinking about swapping JZA80 (Supra TwinTurbo) rear end and gain Torsen LSD in the process. Of course there will be questions about VSS and compatibility, but let's just reserve those for later.

Thanks for you guys' time.

TFW

LOTC

Changing to a JZA80 rear end is not the only option, there is a aftermarket LSD and torque converter for the LS400.

JBrady

I am not positive about the 90-94 LS400 but I believe it is a 3.62.

The 95-97 LS400 has a 3.62 gear ratio.

98+ LS400s have a 3.26 ratio.

No LS400 was offered with a LSD.

Attached is a picture of a stock LS400 differential.

The following info is mostly from an early Supra factory repair manual:
The Supra TT 6speed was offered with a 3.13 initially but was changed to a 3.26 and used a 220mm (8.66") ring diameter. It also used 4 point rubber mount attachment whereas the automatics and non-turbos used 3 point attachment.

The Supra TT automatics had a 3.77 ratio and used a 200mm (7.87") ring diameter.

Both Supra TT diffs were initially torsen type.

The non turbo Supras were 4.27 ratio and used a 200mm (7.87") ring diameter. Clutch type LSD was optional.

JBrady

Another view:

TomWahjudi

jbrady,

Thank you for the information. I'll search for more information whether automatic Supra TT rear end will fit (outside dimension wise). I'd hate to spend the money just to find out that it doesn't fit.

TFW

NA2TT

Hey Tom, this is Joey. I was going to ask the questions for you, but I guess you started the thread yourself.

From the pictures jbrady attached, I don't think the Supra differential will fit. The 2 mounting points of the Supra differential are further apart than the LS400.

Some side notes, 6-speed Supras always uses 3.133 ratio in the US. All Japanese spec 6-speeds uses 3.266 ratio. All TT Supras use 4-point mount (2 side, 2 rear). NA's use 3-point mount(2 side, 1 rear). Also, Supra was never offered with clutch type diff from the factory. It's a TRD option (all models, NA and TT).

If someone can supply the chassis code of the 95 LS400. I can see if any Japanese company makes a LSD for it. JZA80 is the chassis code for the Supra and 2JZ-GTE is the engine code for the TT Supra.


Cheers,

--Joey

TomWahjudi

Joey,

Chassis code for my '95 LS400 is UCF22 (UCF20 series). Engine code is 1UZ-FE. The thing is, RMM offers complete rear end assembly with Torsen LSD inside and 3.77 gear ratio for $1,500 and this thing just looks like it's snatched up from Toyota parts bin. The 3.77 gear ratio (I bet) is the same ring and pinion gears on auto Supra TT and so is the LSD.

It seems that the housings are a little different from the looks of them and I'm not comparing mounting points. The LS400 rear end is different from Supra TT (any tranny) which is different from RMM differential too.

So, I don't know. I'm at the end of the rope here, unless there is more information coming in. I'm still waiting for a reply from RMM to see if their 3.77 Torsen LSD assy will fit UCF20.

TFW

JBrady

Tom,

The 95 LS400 uses 3 mounting bolts as does the NON-turbo Supra... you may want to compare those housings as a possible swap. The Supra has a 4.272 ratio and that would REALLY wake up a 95.

TomWahjudi

jbrady,

I would like to compare those two, but I don't have access to a Supra N/A rear end.

The thing is, Supra N/A rear end doesn't even have Torsen LSD. The most important thing (for me that is) is the Torsen. 4.27 is nice also but that will necessitate speedometer correction. Let's do some calculation to find cost.

Let's say the Supra N/A rear end is $500, TRD LSD (clutch type) is $750. Bearings and seals (I wouldn't let it go unrebuilt after torn apart to install the LSD) are probably around $50. Let's say labor to adjust the R&P is $50. Total is $1350. For $150 more, you can get brand new RMM unit ready to install and you get Torsen instead of clutch-type LSD.

I guess it depends on the price of the Supra N/A rear end, if it was free, then hell yes, it's much cheaper, but what's the chance of getting something like that.

Oh well. Back to drawing board.

TFW

JBrady

Actually LSD was an option on non-turbo Supras but I can't say how to identify them in a wrecking yard.

TomWahjudi

jbrady,

Thanks for the info. I wasn't sure the type of the LSD on Supra n/a diff, but after looking back, you said it was clutch type, my apology. I guess if you could locate a used Supra n/a diff already equipped with LSD, it's going to cheaper. I located a few of them but nobody was sure if theirs had LSD. I know how clutch type LSDs operate, if I can get ahold of a Supra n/a diff, I can tell whether it's open or LSD. I'll just have to search for one.

In any rate, now I'm wondering if the diffs that RMM sells will fit our cars.

TFW