ok I have a 2006 Civic Si coupe and my transmission either needs to be rebuilt or swapped. I think the most cost efficient and time saving way to do this is just to swap the transmission. I saw a K24 standard Accord in a junkyard the other day and thought about getting the transmission. But I thought about how it wouldn't have an LSD and aggressive gears as the Si. But could the LSD and gearing be swapped? (except the 5th gear) for cruising speed. What do you guys think? I know I would be putting a 5spd transmission into a 6spd car. My 4th gear grinds. But I think that would be the syncro. I have never worked on transmissions besides changing the fluid/ clutch/ and flywheel. So I thought I'd ask. Thanks!

 

Fixing your transmission will be easier than swapping the internals into another case and fixing it.

With a grind, be prepared to replace the synchro, slider, hub, gear and shift fork.

 

should I buy an entire syncrotech rebuild kit? or could I maybe get away with just the synchro kit?

 

I would open the transmission up first before ordering. If time is an issue though then I would order a master rebuild kit plus a mainshaft 4th gear from Honda. You can shoot me a PM to order any Synchrotech parts.