Ok here's the deal. I have a 91 Civic HB SI. I am going with a ZC swap and decided to use my SI tranny because I hear it is better. Well my 3rd gear syncro is going out so I need to replace it. How hard is this? Would I be able to do this or should I take it to have it rebuilt? Where do I get the syncros from? Also I was wanting a taller 5th gear for highway use since I travel often. Right not I run about 4K at 85mph. If possible I would like that at like 2-2.5K Reving that hight for a extended time burns serious gas. Also the ZC is going to be turbo since I have a entire kit ready to install.

 

It's not that hard but if you've never worked on transmission, I wouldn't touch it if I were you. You have to buy the whole 3rd gear synchronizer assembly and you can get it from http://www.hondautomotiveparts.com (Majestic Honda).

I don't think it's possible to swap a taller 5th gear over. But what you can do is use the dx differential instead or just get a dx tranny because it has the same gear ratios as the si just with a taller differential gear.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by e30dood &raquo;</TD></TR><TR><TD CLASS="quote">I don't think it's possible to swap a taller 5th gear over. But what you can do is use the dx differential instead or just get a dx tranny because it has the same gear ratios as the si just with a taller differential gear. </TD></TR></TABLE>

Please refrain from thinking.........

88-00 5th gearsets are interchangeable. You have your choice of 5 factory ratios.
.694/.702/.750/.771/.878

You will use MORE gas by lowering the cruising rpms. TOO low and you will bog the motor, use more throttle, and therefore more gas!!!!!!!

I run a 4.250 FD and CRX Si 5th in my 93 DX HB with SOHC VTEC motor. Using 325 cc/min injectors I still get 38 mpg when cruising at 3800 rpm and 80 mph.

 

Has anyone bought a rebuild kit for the trans, like all syncros/bearings/whatever? I was wondering what that would cost.

Before I put in the turbo on my hatch I could get 42MPG w/ 450s My si only gets low 30's, because it is geared shorter. OTOH my uncles nissan truck went from like 20mpg w/ a 5spd to 25mpg w/ a 4spd highway driving because 5th was too tall.

-Dustin

 

Found this thread as I am about to rebuild a CRX HF manual transmission. The kit with bearings, sychros, and seals can be found it BK326WS KIT for about $200 on ebay. If you don't need the Synchros, the kit is about $115. I checked Majestic Honda (part no 23626-PL3-325) and I think they want $130 for the Synchros only..

 

Just an FYI, the mainshaft bearing on the SI/EX is different than DX/LX, which the kit didn't indicate, the rest should fit from the kit.

 

this is good info as i have a syncro crapping out in my si tranny right now....im going to put a junkyard trans in for now then go ahead and rebuild my si ....now the question does the hf 5th gear work in the si trans?

 

^^ will work, you will need to changer out both 5th gears on the counter and mainshaft

 

I'm going the same route basically too. 5th gear syncro crapped out completely finally and I can't shift into it at all anymore. There's a class at the college near by that is for manual transmission rebuilding. So if you get lost there's someone to help your ***. I was thinking about taking it just so I could learn some **** but decided against it in the long run.

 

This is the best thread I found for rebuilding the CRX Tranny, take a look, great pics

http://www.gassavers.org/showthread.php?t=359

 

Just bought the BK326WS kit as a Christmas gift to myself. Will take apart the CRX HF tranny and roast marshmellows by the fireplace..