Saturday, July 19, 2008

D Series EF Civic and CRX Hydraulic Transmission Swap - Wrenchin

As a parent, in order to make things fair you have to treat each child the same as you do your firstborn. With engines, the B-series always seems to get the most attention so it's time for a good tech story with the D-series engines that are becoming more and more popular.

One of the biggest problems with the second CRX and fourth-generation Civic chassis, or the EF as it's also known, is its weak aluminum shift forks. Quick shifts, like you'd do at the dragstrip, place added pressure on the forks, which make them respond by snapping faster than Britney Spears. Losing a shifter fork won't just stop you from shifting, it can also send pieces flying around your gears, making the repair even more difficult.

The newer hydraulic transmissions, which made its debut on the '92 Civics, had a complete internal redo with much stronger stamped steel shift forks. These transmissions are quite strong and, aside from synchro problems, are very reliable. But getting one in your older EF cable-operated transmission-bodied chassis is a big project.

The first challenge is that the EF chassis lacks firewall provisions for the hydraulic piston needed to operate the hydro transmission's slave cylinder. Those with talent and time have mounted one on the inside of the firewall and made a custom clutch pedal mechanism to drive it, but that's beyond what Honda Tuning preaches.

The next challenge is the mount. The newer tranny has a slightly different setup so a bit of welding and fabrication would be needed to make it bolt in. Finally, the speedo sensor can be a problem, but of them all, this is the easiest to conquer.

With so many of these stronger hydro transmissions laying around the junkyards, it was only a matter of time before someone created a complete kit to help EF guys make the swap. When it comes to Hondas and complete kits that someone is nearly always Hasport. The big name in swaps now has a complete bolt-in kit for any of the fanatic D-series guys who feel the need to swap that hydraulic tranny into their EF.

The swap you see here is the most unique and includes a few extra parts, but we'll be sure to make note of what you need if you simply want to put a newer Civic Si hydro tranny in your older EF Civic Si and call it a day. This car is a dedicated drag car and has a ZC twin-cam engine but retains the car's original transmission. The extra is a JDM-only LSD that's found in ZC-engined CRXs and Civics. T