i recently picked up a m2y4 (5th gen base) tranny for my accord, the guy who sold it to me said he didnt know any history on it so i got it for a really good price.

i decided before i throw it in my car i would take it apart and check everything out with it, i could tell the case had been apart before. i was also considering putting in an accord 5th gear for highway (which i found out why wont work)

anyway i decided to take a count of the gear teeth to verify it was infact the correct gearing. according to a faq in here my gear ratios should be:

1st 3.285
2nd 1.956
3rd 1.344
4th 1.034
5th 0.812
FD 4.266

now, by my count i get:

.......main.....counter.....calculated ratio
1st....13..........43................3.307
2nd...21..........38................1.809
3rd...29..........39................1.344
4th...29..........30................1.034
5th...35..........24................0.686
....counter.....diff.
FD.....15.........64...............4.266

now these ratios arent even close to any of the gear ratios listed in the faq and what really has me confused is my 5th cause there isnt any 5th i can find that low for even an accord trans. here are pics for proof of my 5th.



i took a few pics of the 5th gear from my m2y4's countershaft next to one from an h2u2 (f22) tranny i had laying around. you can see why the accords gear wont fit the prelude's countershaft it is too tall.

f22 left h22 right





another odd thing i found was the machining on the h22's 5th as seen here and in some of the above pics:



looks kinda like it was milled down and someone used a grinder to make the oil passages. so i wonder if this is acutally an accord 5th that was modified to fit?

i cant decide if i should put this trans back together and put it in my car or just leave the m2s4 i have in there.

 

interesting, it does look like that gear has been milled down.

 

wow, that's crazy! I'll lok at this more when i'm more awake/active. I just build a zc/si hybrid trans all night

 

hey homey, do this. assemble both shafts full of the gears "aka gear stacks" and pair them next to each other on a table. get a picture of the shafts next to each other and mesh the gears togoether I want to see what they look like when laying like this | |

it COULD have worked out that they used a...****, i have no clue. i'm gonna have to show this to bone.

 

It has definately had the 5th gear machined to fit but I don't even know what some of the other gears might have come out of assuming that there are no gross round-off errors in published gear ratios. You got yourself a 'custom' transmission there.

For the most part it looks like you have a M2S4 H23 'Lude transmission with a nice tall 5th gear. Good for boost maybe? Also for what it's worth the 5th gen H22 transmission is basically the same as the M2S4.

If it is in better condition than your current gearbox then I would swap it out and sell the old one.

Pirate

 

Looks like someone wanted a tall 5th for highway, and they cut down an accord gearset so it would fit. I have wanted to try that!

 

here are some more pics

 

Looks like it lines up pretty well. Was there any modification to the other gear on the mainshaft? Obviously the countershaft has been cut down a bunch. How about the rest of the gears?

Pirate

 

the rest of the gears looked normal. dunno, i guess i will put it in and see what its like.

 

*DREWL* .686 5th!! i want it.. that seems to have been a very custom tranny... i would look over the bearings, and if all seems good, run that bad boy..

 

this baffles me. where did the 0.686 5th gear come from?


i wonder if it came from a k-series or some ****

 

did the tranny shift and spin fine before opening?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bense &raquo;</TD></TR><TR><TD CLASS="quote">this baffles me. where did the 0.686 5th gear come from?


i wonder if it came from a k-series or some ****</TD></TR></TABLE>

i believe it came from the accord countershaft gear having a different number of teeth on the accord mainshaft 5th gear, while the lude mainshaft has more/less to modify the ratio to .686.....

i didnt bother punching #s yet to figure out what exact combo it is, but i would be willing to bet its from an f22a trans

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">It has definately had the 5th gear machined to fit but I don't even know what some of the other gears might have come out of assuming that there are no gross round-off errors in published gear ratios. </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever &raquo;</TD></TR><TR><TD CLASS="quote">i believe it came from the accord countershaft gear having a different number of teeth on the accord mainshaft 5th gear, while the lude mainshaft has more/less to modify the ratio to .686.....

i didnt bother punching #s yet to figure out what exact combo it is, but i would be willing to bet its from an f22a trans</TD></TR></TABLE>

I believe you're both correct

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by homey dont play dat &raquo;</TD></TR><TR><TD CLASS="quote">5th...35..........24................ 0.686 </TD></TR></TABLE>


24/35 = 0.68571428571428571428571428571429

Homey did the correct thing by rounding it to 0.686. Whereas the other sources truncate it to 0.685 When we search for 0.686, nothing comes up, but 0.685...


http://www.hondanews.com/CatID...ves=t

http://hondaswap.com/reference...29132/

Both list 0.685 for the:
94-97 Accord DX/LX
94-97 Accord EX
94-97 Accord Lx/EX Wagon

Awesome

 

up again cause i'm thinking about doing this for a customer

 

I don't think I like the differnence in 4th to 5th gear with the .685 ratio I did manage to pick up a $95 M2B4 of unknown condition and ultimately It'd be nice to put the .787 gear on the end of a stack of M2F4 1-4 gears. Kind of a happy medium.

It the M2B4 gearbos is shot then I'll probably add my spare M2S4 gear set to the M2F4 cases with the LSD.

Pirate

 

Yeah, the ~34% drop from 4th-5th is a bit too much for my personal preference, but this is for a customer that does a lot more traveling than "spirited driving"

I prefer about a 18% drop from 4th to 5th. The tightest that I've seen is the d-series dohc which has a 1.033 4th and a 0.878 5th which is ~15% drop.

Okay now I'm just getting carried away lol

 

10 years later and this thread keeps coming to mind while I'm researching stuff pertaining to the F/H trans build I'm working on.

Made a WTB post on facebook in one of the honda groups I'm in stating that I'm looking for a 4th gen Prelude VTEC 5th gearset of 0.871. Some dude hits me up and says I can have his 5th gearset from his M2F4 if I can help him find a 0.685 5th gear for him.

As luck would have it, I removed the 0.685 5th gear from my F23A1 trans and still have it in a box in my father's barn. While chatting with the dude with this AMAZING 0.871 fifth gear that wants to trade, he tells me that he's definitely down to trade, but his transmission is in his friends house, and that he's still waiting for him to become available so that he can get over there and pull the 5th gear from his trans.

While chatting with him, he made mention of the fact that he wasn't sure if Synchrotech still offered this service of modifying the F22 5th gear to work in a prelude trans. I remembered this thread and linked him to it.

Wanna know who his friend is? @PirateMcFred

Happy 10 year and 1 day anniversary! And to think that I was chatting with Rosko last night and stayed up all night to research trans while I'm in between jobs --- JUST LIKE I WAS A DECADE AGO!!!! ha

 

Thats funny.

Did anyone ever drive a tranny with the 0.685 5th gear in it and give an impression?

Your post made me dig up the ratios really quick, to make sure the gearset I threw out when I moved didn't have anything special. Luckily it was just an M2A4, so nothing neat. I kept the case part that I needed to replace on my M2B4, and that's it.