Prelude Manual Trans Upgrade

[NASOHC]

I have another project.

As most of you know i have a M2S4 Prelude Trans. in my car now that's about to get rebuilt before the NA motor goes in. I've done some research and going to try this to see if it really works. Since I still have my old 5 speed, my plans are to swap the 5th gear from that into the Prelude trans. for lower RPM speed on the HWY. They're supposed to be interchangeable but I never found info. on the completed task to ensure fitment and/or operation. Anyone have further info. please let me know. I'd love to install a Quaife LSD as well with a different final ratio to take advantage of better gearing but I still don't know if I'll be able to fit it into my budget. I will update this thread with my findings. Wish me luck!

UPDATE 5/8/09

Transmission Complete! See page 3 for details.

SPECIAL THANKS:
Jason (AFAccord) for provinding all the info. and Nathan at AUTOTECH (Wavetrac) for Sponsoring part of the LSD and Hal (CalTrans in Santa Ana, CA) for doing the build. Couldn't of done it without you guys!

 

[BadgerType]

AFAccord did it

i believe you just swap the main shaft from the accord tranny into the lude, but dont quote me

 

[EmMinODaGreaT]

I just put a kaaz diff into an h tranny

 

[NASOHC]

I just put a kaaz diff into an h tranny

Kaaz? http://www.kaazonline.com/dbh1854.html

Looks nice, how much and do you know the final ratio?

Thanks!

Thanks Badger, I'm sure he'll run into this or I'll just PM to ask.

 

[BadgerType]

I just put a kaaz diff into an h tranny

indeed

 

[AFAccord]

You'll want to swap both main and counter-shaft 5th gears into the M2S4. The trick is you'll have to mill down the F23's 5th gear set to the same thickness as the H23's 5th.

Here's what they look like, F23 5th on the left...

I couldn't afford any more down time than it took to actually swap the gears, so I had to order the M2S4 counter-shaft 5th just to measure it so I could get the F's 5th machined ahead of time. It was only like $42 from Majestic, unfortunately I haven't seen it since I moved. I gave the machine shop both F-gears, and the new H-gear, and had them mill the F's gear set down to the same thickness as the H-gear. You'll also need to grind some new oil passages after it's been milled, like this...

Since you'll have some down time, you can just pull the gear from your tranny to get the measurement, then reassemble it with the F's 5th gear set. Hope this explains it well enough. Let me know if you have any more questions.

EDIT: The gears are a direct swap. No machining was required when I performed this myself. Just swap both F23 5th gears in place of the H23 5th gears.

 

[BadgerType]

same principle with f22 trannys?

i have my hands on 2 of them, lol

 

[5spd'r]

What is the rpm increase when going to the prelude trans? I don't drive many highway miles but maybe a couple trips to socal from tucson each year. I knew a guy with an Integra type R with a cruising rpm of 5700 (75mph)!

 

[lwlba]

my h22 tranny rpm is at about 3.5 @ 75 mph ish... 4@ 80 ish.

 

[NASOHC]

Here's what's going into the M trans in the coming weeks along with 5th gear from F series.

http://www.wavetrac.net

Local trans. builder in SoCal is doing all the work for a very reasonable cost. Incl. rebuilding trans. as well, obviously.