How-To: Change final drive ratio (relatively) cheaply

[kodyo]

Originally Posted by mcbrawr

Does anyone have a link to the part # for the pinion bearings?

90366-35087
90366-30067

I believe those are the two for the pinion bearings.
90366-50001 is the one for the axle bearings I'm pretty sure.

I'd double check with a common parts diagram online, but those are the ones I ordered for my IS300 pumpkin, which should theoretically be the same ones in the stock diff.

EDIT

This is where I normally order from (has parts diagram):
http://www.toyotaonlineparts.com/aut...ferential-scat

This diagram is saying 90366-35170 & 90366-30108 in lieu of the above. I strongly suspect they might be identical. But if you are rebuilding an FRS pumpkin and not an IS300 pumpkin, probably not worth risking.

[kev60625]

Thank you so much for this thread!

[mrbbs]

Thanks for the information!

Would you know the Toyota part number for the 4.875 final drive? Will it fit the standard 2017 carrier?

[kodyo]

Originally Posted by mrbbs

Thanks for the information!

Would you know the Toyota part number for the 4.875 final drive? Will it fit the standard 2017 carrier?

Just use the 4.88 for the Mk3 Supra (1986-1992) from here:
http://weirperformance.com/finaldrivegears.html

[allmotorrex]

Most of this talk is about the is300 diff so I want to ask and clarify this .....

I have 2 dedicated drift mk3 supras (both 88s) along with 3 spare diffs. 2 have the lsd and 1 does not. My frs is FI and I want a taller gear. Can I directly swap one of my supra diffs into my frs? Pumpkin for pumpkin?

[kodyo]

Originally Posted by allmotorrex

Most of this talk is about the is300 diff so I want to ask and clarify this .....

I have 2 dedicated drift mk3 supras (both 88s) along with 3 spare diffs. 2 have the lsd and 1 does not. My frs is FI and I want a taller gear. Can I directly swap one of my supra diffs into my frs? Pumpkin for pumpkin?

Doubtful, but don't quote me on that. Only Supra part I've heard people use are specific to the ring/pinion gear sets inside the pumpkin.

[BurnetRhoades]

Bit of a necro, but I was watching a Smoking Tire segment where the car being driven was a heavily modified Honda where the final two or three gears were selected from different models of Honda/Acura to improve highway cruising after going with an aggressive final drive.

Has anyone done something similar so that once changing to a 4.56 or 4.88 a non-stock 5th and 6th gear is used so that revs between 60-70 are back at stock or, even better, better than stock? It would be great to be cruising at highway speeds and not hovering around 3K (prior to final drive swap).

[spitsnaugle]

Resurrecting this thread. Not sure if this has been discussed but it appears we can use Nitro Gears&Axel 29-spline gears with a new flange for more gear ratios.

New Flange (ours is 60x60mm)
https://www.justdifferentials.com/YO...yfitkit-29.htm This also leave the option of using a 66x66 flange for a larger joints.

Gears: 3.90 | 3.73 | 3.58

[rixter145]

Originally Posted by spitsnaugle

Resurrecting this thread. Not sure if this has been discussed but it appears we can use Nitro Gears&Axel 29-spline gears with a new flange for more gear ratios.

New Flange (ours is 60x60mm)
https://www.justdifferentials.com/YO...yfitkit-29.htm This also leave the option of using a 66x66 flange for a larger joints.

Gears: 3.90 | 3.73 | 3.58

Do we need to get all of this to do a FD swap?

2012- 2016 Scion FR-S, use with Master install Kit MKTLC100-IFS, solid spacer SKCSTV6, and Yoke fit kit YOKTOYFITKIT-29.

[86TOYO2k17]

Originally Posted by rixter145

Do we need to get all of this to do a FD swap?

2012- 2016 Scion FR-S, use with Master install Kit MKTLC100-IFS, solid spacer SKCSTV6, and Yoke fit kit YOKTOYFITKIT-29.

You just need the ring, pinion, shims, and crush spacer or solid spacer, depending on how many miles your diff has seal and bearing would be a good idea too.

What ratio are you thinking?

[rixter145]

Originally Posted by 86TOYO2k17

You just need the ring, pinion, shims, and crush spacer or solid spacer, depending on how many miles your diff has seal and bearing would be a good idea too.



What ratio are you thinking?

Got it. I'm debating on the 3.9 vs 3.7.rebuilt my motor and I'm using a cd009 tranny. The gear ratio is a bit shorter so the 3.9 will give me the same speed as the 4.1 with stock tranny ratios

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[86TOYO2k17]

Originally Posted by rixter145

Got it. I'm debating on the 3.9 vs 3.7.rebuilt my motor and I'm using a cd009 tranny. The gear ratio is a bit shorter so the 3.9 will give me the same speed as the 4.1 with stock tranny ratios

Sent from my H8314 using Tapatalk

If your going 3.9 or 3.7, then buy the rear diff with gears already installed way easier and cheaper

[rixter145]

Originally Posted by 86TOYO2k17

If your going 3.9 or 3.7, then buy the rear diff with gears already installed way easier and cheaper

I have a os giken LSD on my current pumpkin. Would need to swap it anyways

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[86TOYO2k17]

Originally Posted by rixter145

I have a os giken LSD on my current pumpkin. Would need to swap it anyways

Sent from my H8314 using Tapatalk

Ah then you’ll have to weigh your options, but the os giken is supposed to not mess with backlash and need reshiming, could possibly get the 3.9 diff assembly for 3-400$ and swap over the Giken since bearings are already pressed may be pretty easy DIY. Otherwise you’re looking at about 4-500$ just on labor swapping in ring and pinion if you’re pulling assembly yourself. Now if you can DIY everything thats a different story.