1sFTW

I’m not sure, but when I’m in the neighborhood and I get to third, it downshifts just fine. As shown in the video, it can be smooth downshifting yourself, I just keep forgetting to do it because it’s still new to me. The car will downshift itself but it is not smooth whatsoever. In the video, you can see it goes from 8th to 2nd pretty abruptly.

RRocket

Thanks for the reply.

I'm still inclined to do this mod.

Just want some more details on full throttle runs when you get a chance.

I know from past experience going from a 2.9x to a 3.7x gear made a tremendous and very noticeable difference

1sFTW

Ive done a few quick pulls now, only from 2nd from 20 to 70. It feels like it’s pulling harder, I’ve yet to launch it, I think I’ll wait until friday for that. One thing I can say about the switch is that I feel as if there’s always power available at any gear at any rpm. Even cruising in eighth, I don’t have to downshift to pass, it’ll pick up pretty quick, quicker than stock that’s for sure. I’ll make sure to have my go pro for Friday and of course I’ll have the slips. I’m just hoping I can catch otherwise I believe my times will suffer, I’ll just have to figure out how to launch with the shorter gears

RRocket

And that's exactly what I'm looking for....

1sFTW

Let’s just pray it’s good weather on Friday in J Ville, NC!!

lobuxracer

iTrader: (2)

Mine has never been smooth when I didn't manually downshift. It's always been jerky in manual mode when I let it downshift itself.

1sFTW

I’ve experienced the same, it’s a lot more noticeable in this situation though. In stock, I Could at least see the gears changing in manual mode (at least I think) but with the new diff, the numbers go straight from G8 to G2 then G1. I’ve also been jerky from 1-2 then 2-3. The rest are all smooth, this was with the stock diff and it holds true for the gs350 diff.

Jwconeil

I want to make sure I understand. In auto it drives fine. In manual it drives normal as long as your downshifting it. If you don’t, then it doesn’t want to downshift?

that doesn’t seem like a problem... the whole point of manual is to shift yourself.

did I understand correctly?

RRocket

Yea, I think you understand.

Jwconeil

Anyone know how I can obtain the part numbers for the ring and pinion, and any other parts that I need. I’m going to have this installed on my torsion carrier.

1sFTW

Lexuspartsnow.com has it and it’s gonna run you $$$$. Why not just take the gears from a used carrier? I got the carrier for 145 off eBay.

RRocket

Is it a specific year only fit? Which years should we be looking for? 2013+ ?? Where they different prior to 2013??

1sFTW

I’m not sure about the processes of transferring gears, which is why if the carrier didn’t fit, I would have taken it to get it done at a shop. The final drive ratio is different between the 3rd and 4th gen gs350. I had not a clue it was going to fit, I rolled the dice. My fitment theory came from someone swapping a 2nd gen is350 diff into a 07 gs350 (direct swap). People here have done 2is350 to isf. That’s the only proof I had. I rolled the dice and hoped the carrier housing had at least the same dimensions from gen to gen, which it did. So I went ahead and bought the 2013 gs350 f sport rear differential. (F sport is awd).

RRocket

You sure about that? For 2009, it shows RWD and AWD as 3.769.

Is the housing different from Gen 3 to Gen 4??

1sFTW

What are your sources??
https://pressroom.toyota.com/article...rticle_id=2671 -2011 gs350

https://www.lexus.com/images/ebrochu...GS_Page_15.pdf-2008 gs350

both 3rd gen. 3.727

housing shouldn’t be different. Again, 2is350 to 3rd gen gs350. 2is350 to isf. (Direct swaps). I have just proven 4th gen gs350 to isf (only swapping rear cover because of different mounting position, otherwise everything else matched up, axle splines, mounting with the top hats, bolt holes etc.)

i also verified the rear diff ratio in the 13gs350 by dividing 49 (ring teeth) by 13 (pinion) - 3.769