Ok, fingers crossed this 2001 sc430 diff has compatible axle stubs so I don't have to pay extra in labor for the shop to swab stubs. Only reason i'm concerned is because of this video because his gs430 diff needed to have the axle stubs swapped over, regardless i'm getting a fairly good deal and i'm gonna bring a friend to make a day trip out of it!!!

 

Correction to my earlier post: the 2001-2005 LS430 and GS430 diffs have the axle stub side type designs. Not 2006 and later versions.

And of course the 2001-2010 SC430's 2001-2005 SC430's (and/or their Z40 Soarer counterparts in Japan) all used the same older side axle stub design. Update: The 2006-2010 SC430's worldwide did not use the older axle stub diff design that SC's use despite being otherwise externally identical.

After those model years Lexus switched to non axle stub modified versions of this diff design which we CANNOT use.

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The SC430's should have compatible axle stubs for our cars (Edit/Update: 2001-2005 SC430's with 3.266:1 ratios DO have bolt in identical diff designs but 2006-2010 SC430's do not) since it is a common thing for later (Correction: Early) model year SC430 owners to swap in Supra MKIV TT Automatic 3.769:1 Torsen LSD diffs into their 2001-2005 SC430's to get an upgrade from their factory open diffs (but with a shorter final drive ratio). I haven't heard of issues with those cars cross swapping with MKIV diffs (Edit: except when this concerns 2006-2010 SC430's).

You will most likely need to swap on an SC300/400/Soarer(Z30) companion flange however. Don't impact it on-- follow the SC300/400 or Supra MKIV TSRM for proper reinstallation procedure of that part with a proper torque wrench. I believe the official way calls for a dial torque wrench specifically.

.....

Either way you will at least be working with a diff version that CAN have all the correct parts fitted. You cannot do this with the later 200mm Lexus diffs which have no provision for built-in side axle stubs at all since in those designs the splines are expected inserted and are part of the drive axles themselves.

 

Hi Craig,

Thanks for all the posts related to LSD. Wonderful reading. I am running a 2JZ-GE NA-T at about 14 psi. I am looking to change to a LSD. I still have my W58 in the car. I do not launch the car too hard. Based on all of the many post you have made, I have come away with thinking that if I was running an R154 tranny, I should be running a 200mm Torsens T-1 LSD diff with a 3.76 ratio from a SC/Soarer/MKIV/GS/Aristo. Would that also hold true for a W58?

Thanks in advance,
Bruce

 

Hey Bruce. Glad if I could help in any way.

With boost I think you're doing right to not launch too hard on your W58. It's shock loading to the small gearsets that are the biggest long term risk (even though Toyota did use that gearbox in one turbo engine application-- the Supra MKIII and Z20 Soarer with the 1G-GTE which put out almost the same torque as a 2JZ-GE does).

The W58 has ratios: 1st 3.285, 2nd 1.894, 3rd 1.275, 4th 1.00 and 5th 0.783

The R154 has ratios: 1st 3.250, 2nd 1.955, 3rd 1.310, 4th 1.00 and 5th 0.753

So they are a little different as revs build but not that far off from each other. The W58 has a slightly more aggressive 1st and the R154 has slightly more aggressive 2nd and 3rd. Overdrive is pretty close with the R154 having a very slightly better highway cruising ratio.

With a 3.0L and 14psi of boost using either transmission I personally like a 3.76 final drive ratio. A 3.92 from an SC400 is also good and will (with boost doing the work and 3.0 liters of displacement) feel a little bit more aggressive as if there is a close ratio gearbox. The 3.76 feels like it splits the difference ideally while allowing for good highway cruising RPMs and still maintaining decently responsive gearing around town.

Technically there is another option which I've only heard of a couple of people using. Taking the 3.615 ring and pinion from a 1990-1997 LS400 (or maybe it's up to 1995 for that ratio) and custom rebuilding a diff with those. There is very little anecdotal review on using that ratio in an SC or MKIV with an R154 transmission but of the one person who related their experience with it on this forum or SF many years ago I think that combination is said to have a bit of a more "relaxed" longer geared feel (not in a bad way, just different in feel from the 3.76 or especially 3.92 ratios).

2006-2010 SC430's also have bolt in identical diffs to ours (apart from the companion flange) with the 3.76 ratio. No LSD of course but you can rebuilt it with one.

Edit/Update: Upon further investigation the 2006-2010 SC430 differential internal gears may be incompatible based on evidence shown on a SupraForums thread involving an externally identical side axle stub less 200mm Lexus diff from a 2008 LS460. See post further down in this thread for more detail as to why. No direct confirmation until someone tears apart an '06-'10 SC430 diff to compare and try but based on the other investigation it is more likely there is a slight but crucially significant difference in the ring and pinion inside (more the ring gear). See below for detail.

As for the LSD choice, I feel using a T-1 Torsen depends on how much power you plan to run. I bought my T-1 when my SC300 was still naturally aspirated and I had the diff rebuilt with a 4.27 ratio to maximize acceleration without a turbo (first with a W58 and later with an R154). I later had the T-1 LSD diff rebuilt with a 3.76 ratio once I was running boost but for me still only 12psi max.

On Supraforums the rule of thumb is said to be that once you get up to 450whp-500whp (and beyond) it is best not to use a Torsen T-1 because it doesn't act as predictably under some full load circumstances and the worm an spur gears will be very stressed at those power levels. Best not to chance that if you'll be going that high on power. If you're not going that high then it should be fine.

The super rare (for the USA) 200mm T-2 Torsen (which uses a totally different internal gearing design) is another story as it is stronger and better and supposedly has higher limits as to power holding with predictability.

I'm still running the T-1 in my SC which is at the moment still only at just over 300whp or so which is still very mild. I will continue to once I get my car dyno tuned with the new ECU (I'm guessing but I may go to just under 400whp by then) but ultimately I see an aftermarket 1.5-way LSD as being my better long term choice as the power level climbs a bit.

I think the T-1's are still excellent for the age of their designs and are great for 2JZ naturally aspirated, 1UZ/2UZ/3UZ applications and 1JZ/2JZ mild boost applications. It is night and day to drive one of these cars without and with an LSD. I'm being conservative in my opinion on their suitability for power level because Torsens are supposed to be long term driveline parts that you really just do the 30k diff oil change intervals to and forget about. Same with the smaller Supra MKIII sized and improved T-2 Torsen design in my naturally aspirated rev-happy 86.

But... if you're eventually going to turn up the boost well past 14 psi I think it might be better to look into an aftermarket LSD instead since it is all the same work to have the shop install any kind of LSD.

It was certainly a weird feeling to me to go from years of using the aggressively geared Torsen with the stock non-turbo engine to a temporary 3.92 open diff with 12psi of boost (while I was waiting for the LSD diff to be rebuild with a 3.76 ratio) to finally driving with boost and the R154 + 3.76 + Torsen combination. With the 3.92 open diff under boost there was significantly more steering correction needed in turns and in straight line acceleration. Any LSD changes all of this and makes accelerating and turning much more sure and confident.

 

I always thought the sc300 with the 4sp auto came with 4:01 and the 5sp manual cars came with the 4:27 ratio? And I know that that rear end can be swapped with anything with the 3:23 ratio. Cause there have been plenty of cars that have had the 4:27 rear swapped i to them. I am assuming u got the manual for performance and the fun factor? And swapping in some taller gears will only hurt acceleration so I would leave the gearing alone and just get your speedometer corrected

 

1992-1997 SC300 5-speed manual cars all came with a 4.083:1 final drive
1992-2000 SC300 4-speed Automatics all came with a 4.272:1 final drive

1993-1996 Supra MKIV NA 5-speed manual cars -- 4.272:1 final drive
1993-1996 Supra MKIV NA 4-speed automatic cars -- 4.272:1 final drive
1997 Supra MKIV NA 5-speed manual cars -- 4.083:1 final drive
1997 Supra MKIV NA 4-speed automatic cars -- 4.083:1 final drive
1998 Supra MKIV NA 4-speed automatic cars -- 4.083:1 final drive

No manual non-turbo Supra MKIV was offered for the final model year since it had a 2JZ-GE VVT-i like the '98 SC300.

I bring the Supra MKIV Base NA ratios into this to more comprehensively show what Toyota was doing with the 2JZ-GE engine transmission and final drive combinations at the time from the factory.

You can swap any ratio in the Toyota 200mm diff family of ratios from 3.266:1, 3.615:1 (from a 90-96 or so LS400 diff but only the ring and pinion), 3.769:1, 3.916:1, 4.083:1 and 4.272:1.


.......


If we're talking a stock non-turbocharged 2JZ-GE engine you would be correct to not go with longer gears than 4.272 or 4.083. Without a turbo the engines need help from an aggressive final drive ratio.

Speaking for myself I bought a manual SC300 because I just like driving with a manual transmission. When my car was still naturally aspirated with the stock W58 I swapped from the stock 4.083 ratio to 4.272 for some better naturally aspirated response.

Toyota offered the early model year non-turbo Supra manual cars exactly that way from the factory after all. It was a little aggressive on the highway above 70mph but was totally worth it to me. In a naturally aspirated configuration I like aggressive gearing.

Once I (like Bruce with his NA-T SC300 with a W58) swapped in a turbocharged 2JZ engine the 4.272 final drive was no longer ideal because now with boost pressure doing the work it was better to have somewhat *longer* gearing. With a boost on 3.0L block using a 4.272 ratio and a W58/R154 there was barely any time to build power through boost before having to shift again. Some like this wild combination but I found it to be too much. Plus with boost and longer gearing the revs don't have to be as high at 70mph in the 5th overdrive gear any longer.

With a boosted 3.0L using W58 or R154 gearing it is more ideal to go down to a 3.916 or 3.769 ratio.

With a boosted 2.5L (1JZ-GTE) the factory 4-speed auto ratio was 3.916 and the factory manual ratio was 4.083. With higher output 1JZ manual Soarers some will get longer final drive gears than the stock 4.083 ratio. The .5L less displacement in a 1JZ vs 2JZ block factors in a bit.

With a Nissan CD009 6-speed manual gearbox the ideal ratio usually seems to be 3.266.

With a V160 or V161 it's 200mm 3.266 or the MKIV 220mm diff's 3.133.

With a Tremec T-56 Magnum it's said to be ideally 4.272 or 4.083. I've also heard of 3.916 or at lowest a 3.769 being used but the higher ratios seem to be more preferred because of how the Tremec is internally geared.

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As for speedometer correction that is easy with all the Toyota transmissions (including the rare Getrags) with a Yellr Yellowbox speedo convertor. Very easy to dial in fine adjustments following any final drive ratio and transmission change. They even make a plug-and-play harness for MKIV/SC/Soarer applications.

 

I have the original rear end outta my GS400 I. My garage, it’s got 3:23 ratio and about 100k on it, we can trade straight across if you want? The shipping is probably about $100 for ea ch of us

 

Craig,

Thank you very much for the thoughtful and thorough answer. Sorry it took so long to get back. My mom landed in the hospital this weekend. My plan is to build an LSD on the side and get it ready so all I have to do is swap it in. I found an open diff from a 1998-2005 Lexus GS300 with a 3.92. Does this diff fit in an SC with a W58? If so, it seems like a good one to re-build with an LSD and used the 3.92 gears?

Thoughts?

Thanks again,
Bruce

 

its almost the same gear ratio your running now. If you think your car has to low of gears then you need to find something with a lower number. The 3.92 is almost what you have. The 3:73 is only slightly lower and it’s an uncommon ratio anywhere but Japan. The next option would be 3:23 from a V8 model like an SC430 or GS400. It’s quite a bit taller. It would probably make a good ratio if your at Sea Level and you want good gas mileage more than acceleration. Nobody really ever swaps in higher gear like this so they are easy to find and inexpensive. You’ll find that the LSD is very rare. You’ll have to get an aftermarket one like a Gilken. That’ll be about $2000! Most people just weld up their stock differential and live with the noise and jerky behavior. It’s pull wear out tires a little faster but $2000 would pay for a lot of tires.

 

Bruce,

I am so sorry about your Mom. I've been there with a hospitalized parent too. I hope her situation will be resolved quickly with a full recovery soon.

The GS300 3.92 diff will work very well for what you want so long as you're good with the ratio and yes it will bolt right in after you swap on an SC300/400/Soarer companion flange (or have the diff shop do it).

You may want to find a junk SC differential to get one of those or buy the flange used somewhere. The SC/Soarer companion flange has 101mm spacing between its flex donut holes while the GS companion flange has 111mm spacing. A minor but critical difference for fitment. Follow the SC/MKIV TSRM procedure for swapping on the companion flange and using a new crush nut from a dealer (Toyota dealers sell the same nut for the Supra diffs) and a dial torque wrench.

The gears, so long as they haven't been welded or otherwise broken in someone's drift missile, will be fine to use and are very durable.

Yes, the diff will fit an SC with the W58 gearbox. The rear driveshaft and mounting points are the same for all SC/Soarers. It's only the front driveshaft which is different for specific transmissions.

As for an LSD I recommend an OS Giken Super-Lock 1.5-Way or Kaaz 1.5-Way "Quiet" LSD. The OS Giken is the best of them all. A used Torsen is fine IF you can find one so long as you aren't going to exceed the safe power range I mentioned for it in previous posts. If you already think you may turn the boost up significantly more in the future (and upgrade that W58 to a stronger gearbox while you're at it) then I'd go with an aftermarket LSD.

 

It's not quite similar in feel to the 4.083 gear ratio he's running now. There is a marked difference between how 4.083 with a boosted 3.0L feels and how 3.92 with a boosted 3.0L feels. I was quite happy with the spare 3.92 diff I temporarily ran in in my 3.0L turbo SC. Unlike 4.272 or 4.083 the 3.92 allowed the engine to build boost well and highway cruising was still fine with boost being more available a bit faster than with a 3.769. It just felt a bit like the car had a close ratio gearbox with the 3.92 + boost + R154.

I was not happy at all with 4.272 or 4.083 against a boosted 3.0L. (I'll give the 4.083 its due as the stock ratio for 2.5L 1JZ Soarer manuals but that's a different engine with less displacement).

We have a source for the 3.769 ratio that is more common than MKIV TT Auto diffs: the 2006-2010 SC430 diffs which all came in 3.769 and which can also swap right into SCs with a companion flange swap. That's the other pretty easy to find diff that Bruce could use instead of the 98-05 GS300's 3.92 if he wants.

I'm a fan of either the 3.769 (3.77) or 3.916 (3.92) ratios for a boosted 3.0L with a W58 or R154. Both feel good. One one feels more racy but is perfectly livable... and the other falls within a good overall balance between good response (with boost) and cruising revs.

That being said I am also of the recommendation that if Bruce can he should try to find a 2006-2010 Lexus SC430 diff to start with... (Edit/Correction: After further investigation I must pull back on the 2006-2010 SC430 diff recommendation-- see subsequent posts below in this thread for further info)... IF he plans to stay with a W58 or later an R154 a compatible 3.769:1 (3.77) ratio is ideal... but a 3.92 will work as well for his setup. Honestly just swapping it in without any LSD work would be the cheapest way for him to determine if he likes it or doesn't vs a 3.77 (3.769) from an 06-10 SC430, MKIV TT Auto, JDM Supra SZ-R or JDM Aristo V300 (2JZ-GTE).


3.266 is the ratio from any of the Lexus 1UZ-FE VVT-i or 3UZ-FE VVT-i V8 cars is an option but totally not ideal if paired to a W58 or R154 transmission. It's way too long and will not have good response with his setup. If he had a Getrag V160/161 or Nissan CD009 it would definitely be a much more ideal ratio.


The Torsen T-1 LSDs are very rare indeed. You have to look constantly for a sale to pop up for a long time and be able to jump and drive wherever it is no matter the distance as soon as you can with cash ready to pay. That was my experience hunting one down years ago. They're probably even rarer to find for sale today.

Welding the differential gears puts added stress on more than just the tires and totally destroys the gears.

RHDJapan currently has the Toyota 200mm OS Giken Super Lock 1.5 LSD listed under $1,000 with shipping. I'm not sure how the current tariffs factor in additionally but it should be significantly less overall than $2,000.

 

a welded can be pretty hard to live with but I can think of so many better things that $2000 would buy. Maybe that is a little higher than what you can find a new LSD for. I pulled eBay and found a factory JZ80 LSD and it’s $2000, the least expensive new Giken I could find was about $1500 and it’s a lot better unit. Unless you’re really up there in power and wanting max performance it just doesn’t seem worth the cost.

 

Craig,

Thanks again for the time you invest in helping out the SC community. It is appreciated by so many. Not just the responders, but lurkers and future readers.

On the companion flange concern, can I use the companion flange from my existing SC differential if I get a new crush not from the dealer to install it on the GS300 diff?

Also, thanks for the wishes for my mom. She is out of the hospital and feeling better.

Bruce

 

Okay, Okay, I get the message. I will start the hunt for a 2006-2010 Lexus SC430 diff.

Bruce

 

Quote:
Originally Posted by bbyatv
Hi Craig,

I found this diff on ebay that seems like a good deal (shipped) for $252. The problem is the 6 bolt flanges where the axles connect do not appear to be there? Any thoughts?

Thanks,
Bruce
Bruce,

It seems I missed something regarding the later SC430 diffs. Indeed the axles going differently than our SC300/400 axles do. I’ve seen a similar change in the diff design with LS430 and later rear diffs.

Internally they are identical including the crucial gears. In terms of external mounting points they are identical. And SC430 owners have in the past posted on CL of swapping in Supra MKIV TT Auto LSD pumpkins into their cars with success.

So in this case what I would say is to grab the SC430 diff for the ring and pinion inside it, then grab an SC300/400/Soarer/GS300/GS400/Aristo/MKIV Supra diff to use as the actual outer casing you’ll be building into.

The SC430 3.769 ring and pinion will swap in along with the LSD of your choice during a rebuild and Driftmotion should still sell a 200mm rebuild kit with all new OEM bearings. Only the side carrier shims are not included (since the rebuilder must take measurements for what is needed and order those specific shims from Toyota).

It is a bit more of a chore to do a custom diff build this way. It’s what I did many years ago when building a custom 4.272 LSD diff from two different pumpkins… and then years later rebuilt the same casing again with a 3.769 ratio.
__________________
1993 Lexus SC300 5-speed | USDM 2JZ-GTE | Built R154 | TT Brakes | Gixxer/Bilstein AK's 600/325 | 3.76 LSD
2023 Toyota GR86 6-speed M/T