Type R Club of America

I had a similar experience going from a USDM transmission to a 98-spec JDM. Highway cruising was mostly the same, but on track, I almost over-revved downshifting from 4 to 3 a few times. I was used to the closer gearing and had some scary moments as a result. On the other hand, the longer 4th and 5th are nice at tracks with long straights (Mid-Ohio, VIR, and especially Road America in my experience).

I bought my USDM R with a bad ISB. I've been driving it for 15k miles or so and have had a 4.785 apart on my bench (for a few years) waiting to go in when I take the USDM one out. I have an LS 5th gear and counter I was going to stick in the JDM trans to drop highway revs a bit, but after reading this thread I'm a little confused, and questioning my intended path. I had also intended to make it a more tolerable daily driver when I had planned this path, but I think my goals for this car have changed a bit so I am open to input.

StorminMatt wrote: ↑Sat Dec 28, 2019 3:42 pm The 1998-2001 JDM 4.785FD transmission actually already comes with fourth and fifth from a GSR. This makes fifth gear in the 1999-2001 the same overall as in a 1997-1998 with the 4.4FD. So freeway RPMs are the same between the two. However, using the GSR fourth and fifth gears narrows the gap between fourth and fifth at the expense of widening the gap between third and fourth.

I was under the impression the FD acted as a "multiplier" on the gear ratios, so the same gears in a 4.4FD would have a different output speed (and following, wheel speed) than a 4.785FD, is that not the case or did I simply misunderstand this comment?

I also see that the JDM type R has longer 5th gear than USDM ITR (0.78 vs. 0.84) and the LS has a 0.71. Now that I don't really daily drive this car, I would like to make it optimal for canyons around here. That's why I'm now considering swapping the USDM 5th into the JDM 4.785FD. Any opinions? Trying to envision how this will drive is making my head hurt. Would that make 4/5 too close?

Is there anyone who thinks they've found the "perfect" gear combo for a peppy and fund 4.785FD trans? Thanks for any input.

Thank you for reminder me to get back to working on this thread... If anyone wants to contribute, let's coordinate!

oddomatik wrote: ↑Thu Sep 23, 2021 6:48 pm ...Is there anyone who thinks they've found the "perfect" gear combo for a peppy and fund 4.785FD trans? Thanks for any input.

What are your use cases? What is your engine setup?

I recently built a new transmission using an OEM JDM 98+ as the base, so 4.7FD, but switched to USDM/UKDM 4th & 5th gears to maximize 15'' wheels. I'm also planning to switch cams to broaden + match my power band to this gearing:
viewtopic.php?f=9&t=295&start=20

coolhandluke wrote: ↑Sat Sep 25, 2021 11:37 am What are your use cases? What is your engine setup?

I recently built a new transmission using an OEM JDM 98+ as the base, so 4.7FD, but switched to USDM/UKDM 4th & 5th gears to maximize 15'' wheels. I'm also planning to switch cams to broaden + match my power band to this gearing:
viewtopic.php?f=9&t=295&start=20

Thanks for the link! That's helpful. My car and engine are completely stock and I plan to keep it that way for the foreseeable future. I'm focusing on "drivability mods" for most of my cars right now, and while the original plan was to shorten the overall gearing with the 4.7FD but give myself a longer 5th for slightly more tolerable highway RPMs, I realize that it might only drop the RPMs 200 or so and give an annoying gap between 4th and 5th during the higher speed carvy roads out here. Now that I don't intend to daily this car anymore, spirited driving through both low and high speed twisties is my priority and probably the majority of the time out of the garage this car will see. I can't say I have any complaints about the existing USDM gearing but I do recall a bit of a drop from 3/4 in the JDM trans when I had it in my CRX, so perhaps swapping the USDM gears into it with some fresh carbon synchros(?) is the way to go!

I never liked the JDM 3-4th gear rpm drop at the track I go to...and rather have that RPM drop from 4th to 5th instead if I had a USDM transmission with a GSR/JDM ITR 5th gear and a 4.7 final drive. .

It seems in your use case, canyon driving, that might be better too. especially since you have to be going into the triple digits on the street to go that fast in 5th gear.

oddomatik wrote: ↑Sat Sep 25, 2021 6:04 pm

coolhandluke wrote: ↑Sat Sep 25, 2021 11:37 am What are your use cases? What is your engine setup?

I recently built a new transmission using an OEM JDM 98+ as the base, so 4.7FD, but switched to USDM/UKDM 4th & 5th gears to maximize 15'' wheels. I'm also planning to switch cams to broaden + match my power band to this gearing:
viewtopic.php?f=9&t=295&start=20

Thanks for the link! That's helpful. My car and engine are completely stock and I plan to keep it that way for the foreseeable future. I'm focusing on "drivability mods" for most of my cars right now, and while the original plan was to shorten the overall gearing with the 4.7FD but give myself a longer 5th for slightly more tolerable highway RPMs, I realize that it might only drop the RPMs 200 or so and give an annoying gap between 4th and 5th during the higher speed carvy roads out here. Now that I don't intend to daily this car anymore, spirited driving through both low and high speed twisties is my priority and probably the majority of the time out of the garage this car will see. I can't say I have any complaints about the existing USDM gearing but I do recall a bit of a drop from 3/4 in the JDM trans when I had it in my CRX, so perhaps swapping the USDM gears into it with some fresh carbon synchros(?) is the way to go!

I would keep your eyes peeled for new/used USDM 4th & 5th sets, as these are discontinued now. I'll try to get back to making a template sheet for inputting gear ratios to see the difference in shift points.

aw614 wrote: ↑Sat Sep 25, 2021 9:19 pm It seems in your use case, canyon driving, that might be better too. especially since you have to be going into the triple digits on the street to go that fast in 5th gear.

coolhandluke wrote: ↑Sun Sep 26, 2021 12:03 pm I would keep your eyes peeled for new/used USDM 4th & 5th sets, as these are discontinued now. I'll try to get back to making a template sheet for inputting gear ratios to see the difference in shift points.

Thanks both for the tips! I'll consider the condition of my USDM counters when I do pull it for the swap, and possibly slap them into the JDM one. Looks like the 4/5 gears are at least still available so those can get replaced at that time - just the counters are unobtanium.

Any wear parts I should consider replacing besides bearings, seals, carbon synchros and clutch while I have it apart?

oddomatik wrote: ↑Sun Sep 26, 2021 12:20 pm ...Looks like the 4/5 gears are at least still available so those can get replaced at that time - just the counters are unobtanium.

Any wear parts I should consider replacing besides bearings, seals, carbon synchros and clutch while I have it apart?

That sounds correct but Cris at IRUNOEM can confirm. I recommend adding a second magnet since there is a space, a trick RBoosted717 taught me. While the transmission is out I would also replace the "clutch release" spring, PN 22835-P80-000($6.) I would also inspect the release fork bolt/ball, 22825-P0S-000 ($13), and release fork, PN 22821-P80-010 ($45.) If worn, replace. There is also a tricky Hondabond part number that helps applying to transmission cases but I don't have it handy. Another member here who previously worked at a Acura dealer, chaseacura, helped me find that one when rebuild the transmission for 97 #00171.