Will the ring & pinon gear of a 88-91 Si D-series L3 Cable Transmission (with a Final Drive of 4.2500) directly bolt into a L3 Cable Transmission from 88-91 HF (Final Drive of 3.8800)?

 

im not too sure but if i think the hf transmissions use a "small bearing" case unlike the si's. i did read somewhere that the 88 si transmission is a small bearing but i could be wrong.

 

yes, the countershaft and ring gear will swap right in - you need to unbolt the ring gears from the differential carriers and swap the Si ring gear onto the HF carrier - ring gear bolts are left hand thread

 

Ahhh - so I can't just swap carriers... Cool, Thanks for the info!
I had the idea (probably not original); 1st, 2nd, and 3rd are numerically closer to each other in the HF than in the Si. As I mentioned above, the Si has a deeper final drive. So if I could take gears from one and stuff into the other... It should make a quick little tranny combo.
Thanks Again!

 

Check out ZC/SI hybird transmission

 

Cool. Next Novice question... what is a ZC??

 

what do you mean by "1st, 2nd and 3rd are numerically closer"? - all of the HF gears are really long when compared to a DX, Si or ZC and the drop from 1st to 2nd is really huge - even with the Si final drive, the gearing would still be longer than the DX - the ZC transmission is the one that came in the 88-91 JDM Civic/CRX Si models with the DOHC ZC engine - gear ratios are:
1st = 3.25
2nd = 1.944
3rd = 1.343
4th = 1.033
5th = 0.878
Final Drive = 3.888

 

First; I need to correct myself from above... "1st, 2nd, and 3rd are numerically closer" should read "2nd, 3rd and 4th are numerically closer".
And. Maybe I got some bad info... Check my numbers.

88-91 HF L3
3.2500 - 1st
1.6500 - 2nd
1.0330 - 3rd
0.8230 - 4th
0.6940 - 5th
3.8800 - Final Drive

88-91 Si L3
3.2500 - 1st
1.8940 - 2nd
1.2590 - 3rd
0.9370 - 4th
0.7710 - 5th
4.2500 - Final Drive

So, looking at both 2nd gears the HF is closer to 1 than the Si. Also the stretch between 2dn and 3rd in the HF is only 0.617. The Si is 0.635. Same is true for the 3rd / 4th change. Smaller number = closer distance, right? True between 1st an 2nd is a longer reach - But I’m not drag racing. I'm more of a time attack kind of guy, where I spend very little time in 1st. my life in between 2nd, 3rd, and sometimes 4th. Now, combined with the deeper final of the Si, should keep the R's in the power band. Those are my thoughts - at least.

 

Bump :-)

 

I just want to verify - the countershafts are different and I cannot swap only the ring gear. Right?

 

yes - these are the parts that you need to swap:

 

nice info...