Honda final drive expert help needed.
 

Im swapping a 2008 Honda Fit engine in my 2002 Insight. Gearing is slightly short and I have a good feeling the 03-05 Civic Hybrid FD will swap. 3.6:1 vs stock 4.23:1. With the swappability of other Honda trannys and gears this seems very possible but unlike the K series not very popular. Any insight would be much appreciated.


civic

https://www.hondapartscheap.com/oem-...BlZWQtbWFudWFs

https://www.hondapartscheap.com/oem-...BlZWQtbWFudWFs


Fit

https://www.hondapartscheap.com/oem-...BlZWQtbWFudWFs

https://www.hondapartscheap.com/oem-...ZC1tYW51YWw%3D

Thank you for posting the links to Hondapartscheap, as it's exactly where I would have looked to confirm.

I reviewed a few other things, and I'll just go ahead and post my notes here:

Specs of the trans, which shows the 1-5 ratios:
* Vehicle Specifications | 2004 Honda Civic Hybrid | Honda Owners Site
* Vehicle Specifications | 2008 Honda Fit | Honda Owners Site




My estimations of fit sport teeth count:
3.462 - 45/13
1.870 - 43/23 or 58/31
1.321 - 37/28
0.970 - 33/34 (or 32/33 or 31/32)
0.757 - 25/33 (or 28/37)
F - 4.290 (73/17)

And if my final drive estimations are correct, then 3.600 is likely 72/20.

Mainshaft is same p/n. However the countershaft 2nd gears are different. This is likely because the fit sport has a dual synchro cone 2nd gear, whereas the '04 hybrid is single cone synchro (this is similar to what Honda did for B18B vs B18C1 2nd gear).

Everything looks good, and I would be very surprised if it were not a 100% direct swap. I also checked to see if the 0.711 fifth gear could also be swapped, and everything checks out.


I always suggest replacing the input shaft bearing (ISB) + seal when transmissions are split apart.
ISB: https://www.hondapartscheap.com/oem-...tn-91002ps0013
Seal: https://www.hondapartscheap.com/oem-...k-91216phr003/

Tool: https://www.harborfreight.com/3-jaw-...ller-4876.html

To install new input shaft bearing, drill out the bearing cage of the old ISB (after you remove it), move all the balls to one side of the bearing, pop the inner race out. Place the old outer race on top of the new ISB, then place a 2x4 on top. Tap in with rubber mallet.

Please snap some pictures for me to use in my 'trans library'

If It were me, I'd look into doing something like using a 4.111 final from one of these:

2004 Honda Fit 1.5S (since mid-year 2004 for Japan ) specs review


And then use the 04-06 civic hybrid 5th gear.

Great project that I have wondered about, too. Would love to see pics of process, final product, or both... Good luck.

Thanks for the reply.

I looked at the 4.11 trans but couldn’t find one for sale or any mention of them in the US, if anything I’d like to start with one but I like the idea of hybrid FD and 5th, used transmissions are pricey but new parts are rather cheap, I also would like to run a sub 22” tire as well as 200hp.... LSDs are plenty as well.


I also emailed Frana and he will make anything for $1200x3 min which is a little rich for my blood

I have an insight 5speed still in car that I’d love to use but it looks very different. It has the .710 5th and 3.208:1 FD mated to a gutless engine in a car technically heavier than mine.

In time I will post pics and facts on the main Honda gear ratio chart thread for sure.

Cool. I'll look forward to seeing it sometime. Hondapartscheap represents the housings for the three cars' transmissions as nearly identical. If they are identical, I guess there might be no need to fab mounts--or not much complexity to fabrication if it is necessary.

2002 Insight:
http://ecomodder.com/forum/attachmen...1&d=1526324392

2004 Civic Hybrid
http://ecomodder.com/forum/attachmen...1&d=1526324392

2008 Fit
http://ecomodder.com/forum/attachmen...1&d=1526324392

I wouldn't be surprised if the HCH1 and Fit trannies were identical. They're both L-series engines that were introduced with the Fit, after all.

The insight transmission is going to be somewhat different though. I'd probably skip it since it was "lightened" a bunch (according to the insight encyclopedia) so it probably won't interchange well with much and was built for a weedier engine anyhow.

from this view im convinced enough to buy them and give it a shot, seems like a simple bell housing swap

Yeah, it sure looks like you're correct. Very cool. Very interested.