Final Drive Discussion
 

Hello all,

I know there are one or two threads discussion the Cusco final drive set, but I wanted to open one up for all final drives. Maybe we can offer some tips and tricks to the install as well has what shim kits were used. I'd like to know what the part numbers and brands of the shim kits are. I know a lot have asked and it fell on deaf ears. So maybe we can get it resourced here for everyone.

I hope to soon get one. Just not sure which.

So far we have:

Cusco
4.556

MFactory
4.44
4.67

There are a few other brands, but I have not been able to source them out yet. I've seen maybe a 3.9 and 4.3 in Japanese magazines, I'm just looking for the websites right now. If you know of any, please link them here. Thanks.

Pics would be cool too. Everyone loves pics! :D

Added: Gear ratios for each gear

1st : 3.626
2nd : 2.188
3rd : 1.541
4th : 1.213
5th : 1.000
6th : 0.767

Gear speed chart calculator: http://pw1.netcom.com/~sgalaba/mph.htm

I too have been trying to find out part numbers on shims and stuff like that. I just ordered a final drive kit that I believe I'll be the first one to test. Before I post too much information I'll guinea pig my car first before posting my review of the kit. But to give a little bit of information, it is another 4.56 final drive gear set.

Awesome! I heard a Nissan shim kit will work, but I forgot the part number for it.

Also, I notice a group buy for the MFactory set for cheap. But not many willing to jump in. I'd jump in on it now if I could get it at that price. The Cusco is costly, but I found it for under $900 in USA. I think a lot of USA dealers are over charging for it. I wish JapanParts had it for sale. Mark up on USA dealers seems to be several hundred dollars.

If the money isn't burning a hole in your pocket, wait a bit. The kit I'm getting is priced very well and doesn't require a group buy. I just don't want to jump the gun and tell people to buy it without testing it first. And I wouldn't suggest for you to wait if it was only saving pocket change. The savings will be worth the wait if the product is good.

I'm going to get 4.67 after my coilover, and now doing some research about the shim kit too, it's good to have a thread that talk about this.

If you have the Scion FR-S Repair Manual.pdf downloaded from this site (5009 pages), starting on page 241 is where they take apart the rear diff. Link is here:


There is also a BRZ factory service manual floating around too on this site.

We run the MFactory 4.67 in our race car. We can also add a shim kit to it which is OEM from Subaru.

Be wary of dealers selling this part who:

1. Don't even own an FR-S or know how this part works.
2. Can't supply a shim kit with it.

That goes for any final drive no matter the brand.

A 4.67 is pretty hefty for a daily driven car.

Do you have a part number for this kit? Also, what exactly do you mean... hefty? I know it might not be "ideal" for interstate highway use. But around town I see no issues.

how high is the rpm when its going 80 mph in 6 gear? the car is my daily drive, but I do track alot with this car as well!

I'm looking that up now (rpm at 80 with 4.67), but I found this on Cusco site. Scroll down and you will see shim numbers. It would be nice to have @FT-86 SpeedFactory give shim kit numbers as well... hint hint.

http://www.cusco.co.jp/en/parts_prod...z_rear_di.html

Where's the 3.8/3.9 final drives for us FI folks?

You can buy one from Toyota today for your car. Or from the Lexus parts bin.

O rly, any idea whic cars they come out of by chance? (As I which cars have our xmission and the 3.8/3.9 final drive?)

Using this site to calculate speeds, http://pw1.netcom.com/~sgalaba/mph.htm

A stock 4.1 final at 80mph will be close to 3500 rpms in 6th gear with stock tire size.
With 4.67 final at 80mph it will be close to 4000 rpms in 6th gear with stock tire size.

So a jump in 500 rpms.

Added: Gear ratios for each gear

1st : 3.626
2nd : 2.188
3rd : 1.541
4th : 1.213
5th : 1.000
6th : 0.767

MFactory popped over to our UK site. For those interested, they said they would make the Cusco ratio if enough people were interested. So 4.56 for the same or possibly cheaper as their other FDs ;)

Yeah, I was over there reading your site, I think. MFactory mentioned that the 4.44 ratio was a custom ratio for a customer in Japan. Could you ask them about a shim kit for their gears? That would be much appreciated. Thanks.

That's right, the 4.44 was originally a custom ratio. Just drop them a mail about the shims although my guess would be that they would recommend an OEM kit.

Lexus is300 with a manual tranny is usually a 3.73 gear set. That's the one I'm on the hunt for.

I've been wanting a 4.67 ever since I knew it was available, but I don't know anything about installing a final drive. What is all this shim nonsense?

Are ya'll saying that if you were to only buy a final drive you wouldn't be able to install it?

I figured it would come with everything needed. Is it because they're older FDs that weren't necessarily designed for our cars? Maybe even universal ones?

The shims are needed to get the correct backlash in the gears. If you don't it could be too tight are too loose and result in heavily worn out gears or eating the teeth right off.

A quick search seems like they'd cost about $10-20. Does that sound right?

https://www.google.com/#fp=3869f80cf...shims&tbm=shop

Using the link I gave a few posts above, here is a Nissan shim:
http://www.nissanpartszone.com/parts...129-61001.html

http://www.villagescionparts.com/sho...rchString=shim

Part - 41201D

Tried my best to read the numbers on this blurry pic.

From what I can tell the instructions show the sizes for all of the shims. And if I'm reading it correctly they are consistently going up in increments of .03 mm every time.

Numbers -
90201 35497 - 1.70
90201 35498 - 1.73
90201 35499 - 1.76
90201 35500 - 1.79
90201 35501 - 1.82
90201 35502 - 1.85
90201 35503 - 1.88
90201 35504 - 1.91
90201 35505 - 1.94
90201 35506 - 1.97
90201 35507 - 2.00
90201 35508 - 2.03
90201 35509 - 2.06
90201 35510 - 2.09
90201 35511 - 2.12
90201 35512 - 2.15
90201 35513 - 2.18
90201 35514 - 2.21
90201 35515 - 2.24
90201 35516 - 2.27
90201 35517 - 2.30
90201 35518 - 2.33

Looking for a 373 gear myself before I go FI. If anyone does a group buy once a 373 is found. You can count me in. I will be on the hunt for some 373s.

I got this from our local Toyota dealer for 450 $.

http://www.ft86club.com/forums/showp...1&postcount=34

Will be in my car by Thursday.

Nice!! The OEM 4.56. Let us know how you like it!!

Here is a list of OEM part numbers for those that want different options I found in another thread. Not 100% sure is these work in our cars. Just info I found on the interwebz.
41201-80125 : 3.58
41201-80050 : 3.73
41201-80052 : 3.91
41201-19605 : 4.10
41201-29606 : 4.30
41201-19557 : 4.56

did it come with shims?

So I'm taking this a step further and I got a whole new carrier out of an IS300, which I am then going to install my final gear into.

The reason I bring it up is that Spence over at Weir Performance (http://weirperformance.com/) sells gear kits for the mark 3 Supra, which he knows to be compatible with the IS300 carrier (he's sold them to a bunch of IS owners looking to do final gear swaps). Seeing as the IS300 carrier is a direct swap into our cars, I would think these final gear kits would be swappable into our carriers as well.

It's like that one mathematical property... if A = B and B = C, then A = C. :D

Take this with a grain of salt though. I've not tried taking one of these final gear kits for a Supra and installing it in our carrier; my plan is to install it into an IS300 carrier, which is known to work. Maybe @Jeff Lange could shed some more light on this issue?

Yes it came with shims and seals. But the seals will not fit. I ordered new seals.

Looking forward to your install! Keep us posting on anything you come across.

What new seals part number you need for the install?
How many shims did it come with?
I've read on 1 of the cusco tread that each car have different shims size.

pics? before and after dyno? thx!

Do our car's speedometer have to be recalibrated after the FD install? Has anyone confirmed it with a GPS? Thanks!

No, but the gear selected indicator on the dash may be out. This can be corrected with a decent remap.

At $600 it's a good deal. FDs aren't something most are willing to tackle so that kills popularity. Too many people here are into bolt-ons/cosmetics and won't dig into slightly more difficult parts. The 4.67 wakes this car up and makes it feel like it should have from the factory.

The MFactory gears aren't made as well as OEM but they're solid. My set didn't lay down a perfect paint mark but were shimmed properly, set at 0.008" tolerance, and make no noise as a result.


Dramatic introduction aside, what's the ratio? Manufacturer?


I daily the 4.67, find it on the mild side, and am glad I went 4.67 over 4.56. My last car had shorter gears and spoiled me. I'd go even shorter if I could find a taller 6th gear to drop RPMs on the highway.


With the MF 4.67 on factory tire diameter, here's what you'll see indicated on the speedo:

60 MPH: 2950 RPM
70 MPH: 3500 RPM
75 MPH: 3750 RPM
80 MPH: 4000 RPM


No. I checked the speedo against a GPS before/after installing the 4.67 and nothing changed. The sensor measures wheel speed and isn't affected by the FD ratio.

Changes to your tire's rolling diameter is the only way to change it and it's underrated anyway. 60 MPH indicated is actually around 58-59. Slightly taller tires would make it more accurate.

This makes me happy. I'm going to start looking into the Supra's 4.88 mentioned in the other final drive thread going on right now.

Keep in mind that a 4.88 would be about 4.5% over the 4.67. Take the speed/RPM numbers I posted above and multiply by 1.045 to find your approximate highway cruising RPMs. Without a taller 6th gear, 4.88 might be a bit much. That's the only way I'd recommend going taller.

I don't care too much about 80 mph, I'm more interested in 1st and 6th's top speeds. This isn't my daily driver.

In that case I can't say anything negative about going shorter. The 4.67 is fun as hell. I doubt another 4.5% would be night-and-day noticeable but every little bit helps.

Go for it :thumbsup:

Interesting