SC400 Vs. LS400 Differential

[Lextreme II]

This is interesting topic I found between first generation SC400 and LS400.

 

[Nappa]

Interesting info, can an SC diff be fitted out back of an 1990 LS? Still trying to work out what sort of stall setting would liven up the lex a bit without being too crazy for when i get one through u lextreme guys. In the meantime im looking get the diff ratio changed in favour of quicker acceleration. whether that means changing it altogether or just the internals... Anyone out there done something similar n got some advice?

 

[Lextreme II]

I think there were few guys tried but without success...

 

[UZZ30-Québec]

is this still true that 1st gen LS400 has a 3.6 Gear ratio???

I bet the internals can be swapped?

If so then, going from 3.6 to a 4.27 SC300 diff would do exactly what i want.

 

[UZZ30-Québec]

according to this site, it is true

http://www.carfolio.com/specifications/models/car/?car=25773&Lexus

 

[UZZ30-Québec]

Stock A341E gear ratios directly from toyota (a friend of mine works there)

1- 2.531, 2- 1.531, 3- 1.000, 4- 0.705 ET REVERSE 1.880

Final drive is 3.62

 

[UZZ30-Québec]

according to a gear calculator

the car reaches 81km/h in 1st gear @ 6100RPM.

something's wrong because i can't get more than 70km/h in 1st gear.

49.9mph in the cut-off (6250RPM)

with the 4.27 gear it's 42.3mph

in 2nd gear stock i get 120km/h , the calculator says 70MPH with the 4.27 and 82.5MPH with the 3.62

if those variations between the 2 gears are true (or near) that would mean i could get a real fast take-off LS400. even with stock torque converter (would still be better with modded TC of course) the 2nd gear change is awesome, it would pull very hard.

The site I used : http://www.car-videos.com/tools/spe...io7=&Redline=6250&Increment=50&B1=Recalculate

I used the stock tire size of 205-65-15 but currently i have 225/50/16 on stock SC400 mags (runs a LOT better, not like a boat)

Final calculations are 221km/h in the cut-off on the overdrive LOL.

 

[jibbby]

I've got an extra 1992 SC400 differential sitting around collection dust in my backyard, if anyone wants it for experimental use PM me if you want it for free...

 

[stunna8c8]

if you are looking for an lsd for the ls400 rod millen used 2 make one. i was told i got one of the last ones it was about a year or 2 ago when i had bought it but u never know if they might have any left .

it looks like this http://www.rodmillenstore.com/prodinfo.aspx?partID=RMMGS431

i still have my diff sitting around my friends shop because my ls400 had broke down befor installation so i havent goten to try it out

 

[Blizzy]

I've got an extra 1992 SC400 differential sitting around collection dust in my backyard, if anyone wants it for experimental use PM me if you want it for free...

It looks like you are not accepting PMs.

How many miles are on this differential? Was it malfunctioning in any way when you took it off the car? By free, I assume I would pay shipping and that is it...right?

I definitely would be interested if it was in working condition. If you can send me a PM with info, that would be awesome.

 

[jibbby]

It's in good shape with no problems..Open end differential with 100,000 miles on it... The outside bushings mounts are worn off it, that's it...Interally it's perfect

The only problem is I live I Los Angeles, California and I am not going thru the trouble of wood crating it up and shipping it...It's just too much work....It's for local pick up only...

Soooo Sorryy:chinese:

 

[JBrady]

if you are looking for an lsd for the ls400 rod millen used 2 make one. i was told i got one of the last ones it was about a year or 2 ago when i had bought it but u never know if they might have any left .

it looks like this http://www.rodmillenstore.com/prodinfo.aspx?partID=RMMGS431

i still have my diff sitting around my friends shop because my ls400 had broke down befor installation so i havent goten to try it out

stunna, I believe you will have a problem. The LS400 from 1990-1997 used a 3 point differential carrier housing. This was changed in 1998. I believe all the SCs and GSs used the 4 point carrier housing same as the Supra. Unless you exchange internals (not certain that is possible for the torsen LSD) or change to a completely different rear suspension you will not be able to install the LSD you purchased from Millen in your 94 LS400. The Millen part was simply factory assembled carrier housing and torsen lsd assembly from the 1993+ Supra automatic twin turbo cars.

 

[JBrady]

It's in good shape with no problems..Open end differential with 100,000 miles on it... The outside bushings mounts are worn off it, that's it...Interally it's perfect

The only problem is I live I Los Angeles, California and I am not going thru the trouble of wood crating it up and shipping it...It's just too much work....It's for local pick up only...

Soooo Sorryy:chinese:

I am not sure about "perfect".

One of the interesting aspects of the Toyota / Lexus differentials are that the contact between the spider gears and the ring carrier seem to become worn with use to the point of creating friction. This friction seems to act very much the same as the clutch packs in a conventional clutch style LSD. The result is many older Lexus SCs and LSs will actually have an unintended limited slip differential. Lexus did not offer any models until the IS300 with LSD and yet many older SCs and LSs will spin both tires on a hard launch mimicking LSD.

So, while the 100k mile diff that Jibbby has may not be perfect... it may actually function as an LSD. I do not know the effects of using different diff fluid such as a synthentic on this anomoly. Nothing promised or implied here merely an educated guess based on evidence. I have no idea what the specific part that Jibbby has will do or not do other than probably work.

 

[Blizzy]

I am not sure about "perfect".

One of the interesting aspects of the Toyota / Lexus differentials are that the contact between the spider gears and the ring carrier seem to become worn with use to the point of creating friction. This friction seems to act very much the same as the clutch packs in a conventional clutch style LSD. The result is many older Lexus SCs and LSs will actually have an unintended limited slip differential. Lexus did not offer any models until the IS300 with LSD and yet many older SCs and LSs will spin both tires on a hard launch mimicking LSD.

So, while the 100k mile diff that Jibbby has may not be perfect... it may actually function as an LSD. I do not know the effects of using different diff fluid such as a synthentic on this anomoly. Nothing promised or implied here merely an educated guess based on evidence. I have no idea what the specific part that Jibbby has will do or not do other than probably work.

I was going to swap out the differential unit itself for a Torsen. I was more interested in the ring, pinion, and pumpkin itself.

Although, that appears to be a moot point since the differential is for pick up only.

 

[jibbby]

I would call around to local import junk yards near you and see if you can locate either the SC400 Differential you are seeking out or even a 1993-98 supra TT automatic rearend LSD... That's how I found my Torsen LSD at the yards for $500... Most open end Lexus differentials should sell for no more then $300 used...

Good luck...

 

[stunna8c8]

stunna, I believe you will have a problem. The LS400 from 1990-1997 used a 3 point differential carrier housing. This was changed in 1998. I believe all the SCs and GSs used the 4 point carrier housing same as the Supra. Unless you exchange internals (not certain that is possible for the torsen LSD) or change to a completely different rear suspension you will not be able to install the LSD you purchased from Millen in your 94 LS400. The Millen part was simply factory assembled carrier housing and torsen lsd assembly from the 1993+ Supra automatic twin turbo cars.

so the only way i would be able to use the lsd on the car would be to swap internals?

man im pretty confused it was listed under ls400 when i got to the site ( a while ago ) . also the shop that brought it in for me had called and asked them if it would fit my ucf11 .

im planing to buy another LS so any help with this is greatly apreciated

 

[stunna8c8]

okay so i did alittle more info on this seaching around this forum

by jibbby

LSD's that are available for the LS's/SC4's are the TRD, TORSEN, KAAZ's, etc...The cheapest LSD is the used Torsen which comes off the 1993 + year Supra TT automatics...TRD is probably the best....KAAZ is the most aggresive


so im guessing i can take out the lsd from the housing(pumpkin) and put it into the ucf11 one? can i keep the ring gear from the supra one or should i keep the ls400 ( if possible )

and im not sure what the 3/4 point differential carrier housing means ?
im still a newbie with diff's so if anyone knows itd be helpfull

 

[Thermactor]

Anyone know the gear ratio on the MkIV Supra automatic? I wonder if there is a steeper drive ratio that can be put into the LS diff, like a 3.2.

 

[stunna8c8]

3.76 i think i could be wrong

 

[cribbj]

Stunna you're correct; for the A/T's, the final ratio is 3.76, and that diff has the small (200mm) ring gear.

The 6spd Getrag's diff has a 3.133 ratio, and it has the larger 220mm ring gear.