Hello, I have a 91 si civic with cable tranny, with close ratio 1 to 4 gears and longer 5th the gearbox is perfect for my driving, trackdays and going to the track with the car.But my second gear start to grind and it wont let shift in higher rpms even with the new oil.I have another tranny from del sol but its a hydro tranny but Is equiped with mfactory caron kit.So my questio is can I use the carbon synchros from the hydro tranny to the cable tranny?on the carbon synhros it said

For the D-series SOHC, the synchros will fit 1988-2000 Civic/CRX/Del Sol SOHC D Series Transmissions.
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Yes, the synchros are a direct swap. The problem is probably with the shift fork and/or dog teeth on 2nd gear.