I have a 90EF Si civic that needs a new transmission. (Please keep in mind that this is a race car running H4 honda challenge rules) I'm not suppose to be switching ratio's

So I posted in CL looking to purchase another one. Now I’ve I got everyone and their mother telling me that their transmission will work on my car (i.e off a y8 off a zc and 4 speeds all kinds of crap)

I’m under the impression that only a Si D16a6 trans will fit my car. I have an OBX LSD with 40mm bearings, 7lb fly wheel, new clutch and pressure plate.... and I don’t want to have to go and buy all that stuff again.

Can you guys tell me what will work on my car – if I have to crake a few cases to make one work too thats ok.

Thanks in advance.

 

Any L3 transmission will work with your vehilce. This includes ones from an Si, DX or ZC. You want to stay away from the HF or Std ones because they use axles with a smaller shaft. Your best bet is to locate an Si or DX one and just swap internals since you have an aftermarket LSD and you have to keep the same gear ratios (DX are the same as Si except fifth gear). The cases will be the same. Good luck though, these things are getting damn hard to find.

 

Well since the CCR states that you can't really swap the trans the DX trans has the same gear ratios but a different final drive. So you could swap your final drive into the DX case and rock and roll. And keeps it all legal.

Double check me on the gear ratios though.

89-91's DX/SI trannys use the same clutch, fly etc so stay away from the 88's. You need stay away from ZC trannys since they are different gear ratios.

(appears Wizco and I were typing at the same time )

https://honda-tech.com/zerothread/1508680 look at the tranny links

https://honda-tech.com/zerothread?id=1551508

 

if you want to keep your LSD and all your clutch/flywheel you need to find an 89-90 Si trans.


all USDM SI trans have the same ratios but have diff input shaft, clutch flywheel, and bearing sizes depending on year.


i wouldnt be suprized if you buy a used trand and get the wrong one on acident though

 

Ok heres the deal. Numbers on the case DONT MATTER!! You need to know what year the car was and obviously it has to be an Si if you cant change gear ratios. Si's have a shorter final drive. 89-91 civic/crx have same input shaft so you should be able to keep clutch and all no problem. Now an 88 has a different one. Unless you know for a fact that its the correct year you'll prolly be buying new clutch and accessories! 91+ civic I honestly dont know what they used in those. Hope this helps.

 

This is most helpfup -

How do you tell the difference between the difference models of ZC, SI or DX?

I plann on taking one of my axels with and a spare clutch plate to make sure things match up... any other suggestions

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NW89Hatch &raquo;</TD></TR><TR><TD CLASS="quote">This is most helpfup -

How do you tell the difference between the difference models of ZC, SI or DX?

I plann on taking one of my axels with and a spare clutch plate to make sure things match up... any other suggestions

</TD></TR></TABLE>

https://honda-tech.com/zerothread?id=1551508


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RACINTWEEK &raquo;</TD></TR><TR><TD CLASS="quote"> if you want to keep your LSD and all your clutch/flywheel you need to find an 89-90 Si trans.


all USDM SI trans have the same ratios but have diff input shaft, clutch flywheel, and bearing sizes depending on year.


i wouldnt be suprized if you buy a used trand and get the wrong one on acident though </TD></TR></TABLE>

Not really true. 88 had different input shaft spline count. 89-91 DX, HF, Si are the same. Just different gear ratios.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 65stang90crx &raquo;</TD></TR><TR><TD CLASS="quote"> Si's have a shorter final drive. </TD></TR></TABLE>

He's using the same LSD, so he will keep the same final drive

 

the only L3 transmissions with the 40mm differential bearings are from the 88 & 89 Si and 88-91 ZC - everything else has 35mm bearings - 90 and 91 Si have other bearings that are larger than what is in the 88 and 89, like input shaft, etc. - what is wrong with the transmission you have? you may have to put together one using parts from different transmissions

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jlicrx &raquo;</TD></TR><TR><TD CLASS="quote">the only L3 transmissions with the 40mm differential bearings are from the 88 & 89 Si and 88-91 ZC - everything else has 35mm bearings - 90 and 91 Si have other bearings that are larger than what is in the 88 and 89, like input shaft, etc. - what is wrong with the transmission you have? you may have to put together one using parts from different transmissions</TD></TR></TABLE>

Wait wait... Quaife UK made a misstatement about the size of bearings on 90-91 CRXs because they used a 90-91 EX (35mm) case for testing...that misstatement got spread in a bad way. 90-91 CRXs can use the OBX 40mm peice with no problems.