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Super Moderator
10,734 Posts
Discussion Starter #1 (Edited)
Civic K20Z3 transmission is a popular choice for RSX owners but there are some things you need to do for it to work on an 02-04 RSX. Some parts of this DIY does not apply to 05-06 RSX.

Pictures for this DIY were taken at different times over the span of a month or so, so if it does not necessarily follow the text, just keep this in mind.

1 - Acquire trans
Get your Z3 trans ready for surgery

2 - Take it apart
Open her up. First thing you need to do is install an 02-04 speedo ring gear onto the diff. Part #41312-PPP-000.
It is a slight press, just use a hammer and flathead and start lightly tapping it on. It will slide on easily doing it this way.

3 - VSS sensor
3a - On the case, remove the plug for the fill hole.

3b - You will now need to bore out this hole until your VSS sensor fits snugly.
Once you bore the hole out enough (keep test fitting the sensor), you need to drill and tap a hole for a 10mm bolt to hold the VSS sensor.
Clean the case out thoroughly, make sure there are no shavings in there.

4 - Inspect/replace/upgrade
Now is the time to inspect/replace any worn parts: synchros, swap gears out, etc while you have the tranny apart.

5 - Reassemble
Reassemble the transmission but do not add hondabond yet to the case halves. Put a few bolts in so it doesn't split apart on you, doesn't need to be them all.
Use a marker and put a dot on your VSS sensor sprocket and fit it into the hole you made.
Spin the shaft and make sure the VSS sprocket is catching properly, aligned, and turning with the speedo gear.

If it is not, you may have bored the hole out too large and the VSS is not pointing straight downward. Find the proper position for the VSS and proceed.

** NOTE ** This step may seem like a PITA but you don't want to assemble the entire trans without making sure your VSS is mechanically working and find that out after you've swapped it in. Put in the time now.

6 - VSS Pt. 2
Once your VSS is catching properly, take some hondabond and apply it to the senor and place it into the hole you bored out. Secure it with your 10mm bolt.

Now you can assemble the halves together fully with hondabond along with all the other small pieces all over the transmission.
Not going to go over that, if you took it apart, you can put it back together.

7 - Shifter mech
You cannot use the Z3 shifter mech. You need a RSX mechanism. The case has two holes that will line up to the RSX shifter mech.
The other two must be drilled and tapped, which is not really required since two bolts may really be enough especially with hondabond, but I decided to drill and tap the other two.

Once you are done you'll have this. Picture shown after completed.

8 - Cable holder
The Z3 cable holder must be swapped for an RSX one.
Two of the 3 mounting holes will be threaded and ready to accept a bolt. You don't need to tap the third but I did.

The third bolt (middle one) I cut to shorten it as I did not want to drill too deep into the case.
With bottoming taps, it doesn't cut threads near the tip of the tap, so this was my solution.

Now you're all done

Finished and ready to swap into your car. Enjoy your new transmission!

Wrote this pretty late so if I'm missing anything I'll edit another day. :sleep:

Super Moderator
10,734 Posts
Discussion Starter #7
This is more specific to 02-04 owners, so if you have a base 05-06 you do not need to do some of it, specifically the VSS portion.
The rest of it is required if you want to use a Z3 trans, in any year/trim RSX.
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