Hello all, I am new to this forum but not to forums in general. I reside in the Houston, TX area. I used to own a 7mgte Supra a few years back, and am getting the bug to have a sports car again, but with a kid I’d rather have a 4 door and some luxuries. I’ve always liked the GS300 body style, and not to mention it has the 2j already. I currently do not own one as of yet, I’m still deciding between SC300 and GS300, but would prefer the 4 door over two. I’m currently in the build sheet process while deciding which model and waiting for an example of one in a decent price point and options that I want(interior color and condition mainly). Anyways, I am a sales rep and drive everyday around Houston for work both city streets and highway, but I want something sporty, that can handle the power and still get me the best gas mileage possible. My goal for dd power will be 550-600whp. So that takes out auto’s and w58. R154 would work fully built, but that tranny shifts hard, is getting more expensive by the day, harder to find, and is only a 5 speed. I’ve been researching, and the cd009/a seems like a great option, and I can get a brand new one for $1800. It can handle power, smooth shifts, kits to make it fit in factory auto location, and a 6th gear(even better gas mileage). My question, that I cannot seem to find, is what rear end would be best to use due to gearing for good power but also best gas mileage(I know you cannot have both and there must be compromise), but also best for keeping the speedometer as close to correct as possible. Gs300 factory with aftermarket lsd, sc300 with aftermarket lsd, Supra tt auto, or Supra tt 6 speed rear end? I know the Supra 6speed would require me to have to swap to Supra 6sp axels. I know R154 route, it is best to get the Supra tt auto rear end, but being as the cd009/a is 6 speed, I don’t know if that makes a difference. I’m not real great at determining the factors on that kind of stuff, like rpms in certain gears, and torque conversion and output and so on, so I am turning to better men than myself for the answer. Thank you in advance for any and all responses!!

Kyle

The factory GS300 rear is a 3.73 and I believe the Supra TT LSD is a bolt-on swap. However, keep in mind that the CD009 has basically the same overdrive ratio as the stock A650e while the first five gears offer closer spacing. The first gear of the CD009 will be shorter than the A650e and with boosted power you may run out of revs real fast.

The diff from the GS400/430 is a 3.27 and I would personally use that for any high power application with either the A650e or the CD009. You’ll get the length you need from the starting gears and lower RPMs on the highway. However, getting a LSD into the 3.27 is a little more of a challenge.

Awesome info. Thank you. Is the GS400/430 rear end a direct replacement for the 300? If so, what is it about that diff that makes getting a LSD in there hard?

Ok I just did a little research on that, and supposedly the rear diffs are the same from sc300 and gs300. Is that correct? If so, apparently the 6sp Supra diff bolts up, I would just need the 6sp driver side axle as well. That has a 3.13 gear in it, and has the lsd already. How would that affect first gear? Would it take longer to build power? I’m fine with a little lag, like I said it’s mainly just for a fun street car, but it should give me a longer first gear and be better on gas at cruising speed on the highway right? Not to mention it’s beefier, which I like.

Ok so I finally found the answer I believe. The gs400/430 can swap right into the GS300. I can just buy the entire pumpkin and add an aftermarket lsd. The driveshaft mate is different, but that’s not an issue as the Collins kit for the tranny swap has all the different options for all the A series diffs. The only remaining question I have, is why did you say adding an lsd to the 3.27 would be difficult? Everything I read is that it fits no issue.

I agree ☝🏽 with everything, btw 2gs 300 is a 3.92

i installed a TT Torsen in the 400's 3.26 in my GS gte swap, fairly simple , whole project piecemeal cost me $1600 +/- installed

$800 TT Torsen
$120 used 4XX diff
$175 figs bushing kit
$120 oem diff rebuild kit (seals clips bearings etc)
$350 install

its not difficult at all, it's all drop in

Where did you get the rebuild kit from? How does it affect your speedometer? Is it off, plus or minus and how much if so? Is there a fix? Thank you both for your input and pointing me in the right direction. I know enough at least about motors and turbos to do the swap, but just now starting to learn about tranny’s and diffs and gearing. I want to do everything at once, in one shot. Replace as much as I can with new or upgraded parts also.

Glad to hear it was easy. Everything I read talked about setting the contact point on the pinion gear and fancy tools and stuff like that.

Maybe you’ve got what it takes for the LSD carrier swap. I sure don’t!

Eicca my trans shop did the work , fairly straightforward.

Wanna , spedometer is fine everything is working as normal.

rebuild kit I ordered from Toyota I'll provide the link I got the info from
2 of each

www.clublexus.com/forums/performance/250495-another-limited-slip-diff-installed.html

Awesome info! Thank you. I will definitely be having a shop do the work on the differential. I will be doing everything all at once, and I don’t want to worry about not doing it correctly, plus apparently needing some special tools. How much torque are you running on that rear end? My last concern is if it will handle the power I plan on, which is mostly 550-600whp daily and maybe 3-4 drag strip nights a year at most at higher levels, maybe 700-750whp. The only upgrade I could really find for stronger rear end and axels is almost 7 grand, short of going 6sp tt rear end, which is about 4 grand used from what I’ve been seeing.

Haven't dyno'd yet , I'm bpu at 18psi , hks fcd / Sld, Upg'd valvebody, and 3.26 Torsen I'm guess about 400 tq

soon , I need to take more pics

Lexlova:
Those seats are sick!

Kitabel:
750-ish will be on a race tune with race gas. My daily tune will be in the 550-600whp. I said before, I know I cannot have the best of both worlds, but I can get the best that I can for sure. The gearing setup that was mentioned will be perfect, decent cruise rpms on the hwy, and JUST under what my expected powerband will be, just out of boost, but with press of the gas peddle, one to two seconds I should be right in the beginning of my powerband and in boost, or I could just downshift also. I mean the Caddy CTS-V makes what I plan on running on the street and doesn’t get 7mpg, so why should I?