Note: At this time I have chosen to not disclose where I have sourced my parts from. Any question that I receive asking me this will be ignored.

Mainshaft #1 - (3.933, 2.038)

Shorter first gear, which is less ideal, however its taller 2nd gear makes the 2nd → 3rd shift closer (less RPM drop). This would be more ideal for road racing where rolling starts / 1st gear isn't utilized.

Mainshaft #2 - (3.625, 2.115)

-Slightly taller 1st gear but shorter 2nd gear. This provides a closer 1st → 2nd shift, however it widens the gap between 2nd and 3rd. This would be more suitable for those that care a lot about the 1st → 2nd shift.



There are also a few options for 6th gear. (0.848, 0.777, 0.734, 0.686, 0.653). I prefer the shorter, 0.848 sixth gear, as I prefer my 5th → 6th shift to be very close (most aftermarket close-ratio performance gears are setup this way). However most people that I've talked with and have built transmissions for prefer to have their 6th gear as a tall overdrive gear.



Final drives: There are 5 available, however there's inconsistency between the # of ring gear / differential bolt holes. Some ring gears have 12-bolts that fasten it to the LSD / diff. Some have 14, others have 16. I will get into this on a further, subsequent post.

1st = 3.933 or 3.625 (either 3.933 / 2.038 or 3.625 / 2.115 -- cannot use 1st from mainshaft #1 and 2nd from mainshaft #2)

2nd = 2.038 or 2.115 (again, you cannot mix and match 2nd from mainshaft #1 with 1st from mainshaft #2)

3rd = 1.529

4th = 1.190

5th = 0.976

6th = 0.848, 0.777, 0.734, 0.686 or 0.653

Final = 3.286, 3.55, 3.842, 3.90 or 4.111

29-spline - This is the normal J-series FWD size.

31-spline - Larger size that AWD TL + FK8 + Accord Sport 2.0T use. -- I am able to make a 31-spline FWD trans. I'm still sorting out the custom axles

OEM Acura CL-S, 2004-2008 Acura TL. - (12-bolt ring gear / 29-spline axle)

* MFactory Helical - (12-bolt ring gear / 29-spline axle)

*

* Quaife FK2 / FK8 Helical - (16-bolt / 31-spline axle)

* HPD (Honda Performance Division) Clutch/Plate -- (I speculate that HPD is just selling the Cusco LSD). They apparently offer this with whichever ring gear bolt pattern & axle combination you want. Must be HPD member to purchase. . - (12-bolt ring gear / 29-spline axle)- (12-bolt ring gear / 29-spline axle) Cusco Clutch/Plate - (16-bolt / 31-spline axle)- (16-bolt / 31-spline axle)-- (I speculate that HPD is just selling the Cusco LSD). They apparently offer this with whichever ring gear bolt pattern & axle combination you want. Must be HPD member to purchase.

I posted athat documented this. I want to re-cap this, and post some of the updates.A pure OEM Frankenstein transmission that I have built to install in myHowever, due to the fact that Honda made/makes many different clutch housings (aka 'bell housing') that fit this transmission, I can make this fit many, many different engines by merely changing out the clutch housing. This is Hondas strongest manual transmission, in other words, it is not "J-series" specific, and this is applicable to anyone that desires Honda's strongest manual transmission. This transmission is most similar to thetransmission (which is very similar to the). -- This is basically the 'one Honda transmission to rule them all'Due to the fact that I began this project with the intention to improve the stock, J-series FWD transmission, I will be listing the benefits that it offers- larger diameter mainshaft.- Closer-ratio 2-6 gears + numerically higher final drive- (stronger + superior synchronizer functionality that last longer and offers more 'stopping power' (think of synchros as 'brake pads' for gears)).- Can be adapted to work on nearly all relevant Honda engines by simply changing clutch housings (C-series, K-series (K20A, K20Z, K24A, K24Z), K20C (FK8 Type R, 2018+ Accord Sport 2.0T), J-series (Both old and new engine/transmission bolt patterns), and possibly more) -- (Update: Can also work on turbo L15 (2016+ Civic Si 1.5T) AWD).- Can be adapted to work in both FWD & AWD configurations on all the above engines except no AWD for C-series or AWD old J-series.In January 2017 I bought a full J32A2 6MT swap from a wreckedthat I came across in a junkyard. II had already begun compiling tons of transmission data for my own spreadsheet (D-series, F-series, H-series, B-series, K-series). When I plugged in the J-series FWD ratios, I immediately noticed a few abnormalities and (of course) I thought the gearing was awful. Since I have been building hybrid-geared Frankenstein Honda transmissions since 2004, I began researching to see if I could find some ways to improve the gearing. After doing much research, more reverse engineering, and even more reverse engineering, I wound up purchasing an overseas transmission to inspect. When I received this first transmission, I had reverse engineered it so specifically and so accurately -- When I finally received it, I opened it up, counted all the teeth, measured everything, and I wound up being 100% correct about EVERYTHING. I then purchased 5 additional transmissions and purchased over $3000 in OEM Honda/Acura parts from Honda/Acura USA, Honda Europe, Honda Japan.In addition to the 3.55 final drive () and the 3.842 final drive (), I discovered two more; 3.90 and 4.11.After I figured out the final drives, I then began to figure out a way to optimize the 1-6 gearing so that it was closer-ratio. Upon researching this and testing out options, I also came to realize that Honda 'upgraded' the J-series trans by giving it a larger diameter mainshaft along with larger sized 3rd/4th and 5th/6th synchro hubs. We first saw this in the US in thetrans. Additionally, Honda also used this design in the, as well as the. The FWD J-series mainshaft is 42mm in diameter for the 3rd gear needle bearing race. The larger diameter, 'big-shaft' AWD J-series and the K20C trans is 48mm in diameter for the 3rd gear needle bearing race. Furthermore, the 'big-shaft' AWD/K20C trans has larger synchros, synchro hubs/sleeves for 3/4/5/6 gears.To begin, here's a table that shows some specifications of the J-series FWD gear ratios that Honda offers vs the ones that I can offer. I have listed the shortest (numerically highest) 6th gear in both of my BenseBuilt configurations, however there are more options, which I will list belowThere are two different mainshafts that I can use. For those that don't know, the mainshaft is a 1 piece machined shaft that has 1st and 2nd gears machined into it. In order to change 1st & 2nd gear ratios to anything else, a custom mainshaft, reverse, countershaft 1st, countershaft 2nd gear would need to be made. I have begun working on this and Iable to get a custom setup made, but this will be a project for a later time. For now, these are our only 2 options. (FWIW, I prefer mainshaft #1)