K20Z3 transmission

K20Z3 transmission

Drivetrain Manual transmission with limited-slip differential Verified Modification Required

Compatibility Overview

Source Vehicle

Civic Si (K20Z3)

Target Vehicle

RSX

Years: 2002-2004

Installation Difficulty

Easy Basic tools
Moderate Some experience
Difficult Skilled work
Expert Professional

Reference

K20A specs → D14A1 specs → K20Z4 specs → LEB-H5 specs → K20Z2 specs → B18A1 specs → K20Z3 specs → K20A3 specs → D16A6 specs → K20Z1 specs → K20A2 specs → D16Z6 specs → D16W4 specs → EA specs → EC specs → ED specs → EE specs → EH specs → EM specs → EN specs → ER specs → ES specs → ET specs → K20A1 specs → K20A4 specs → K20A6 specs → K20A7 specs → K20A9 specs → K20B specs → K20Z5 specs → PPL Cylinder Head → PPL ECU → PPL →
The draw of this swap is the factory limited-slip differential in the K20Z3, which the base RSX transmission lacks. The gearbox does not bolt in as-is: it requires the RSX speedometer ring gear, an RSX vehicle speed sensor fitted into a bored and tapped case, an RSX shifter mechanism, and an RSX shift cable holder. Two of the shifter mechanism's mounting points and two of the cable holder's holes line up with existing threads; the remainder can be drilled and tapped. A base 2005-2006 RSX does not need the vehicle speed sensor machining, but the shifter and cable holder swaps still apply to any year running a Z3 transmission.
The case must be opened and machined before the K20Z3 will work in a 2002-2004 RSX. A 2002-2004 RSX speedometer ring gear (part 41312-PPP-000) is pressed onto the differential. The fill-hole plug is removed and the opening is bored out until the RSX vehicle speed sensor seats snugly, then a hole is drilled and tapped for a 10 mm bolt to retain the sensor. During reassembly the sensor pickup must be trial-fitted and confirmed to mesh with the speedo drive before the case is sealed with Hondabond. The Z3 shifter mechanism and cable holder cannot be reused and are replaced with RSX units, which may require drilling and tapping additional mounting holes.

Important Caveats

  • • The vehicle speed sensor bore is critical; if bored too large the sensor cannot point straight down and will not read speed. Trial-fit and spin the shaft to confirm the pickup engages before sealing the case.
  • • The 2002-2004 speed-sensor work is not required on a base 2005-2006 RSX.
  • • All metal shavings from boring, drilling, and tapping must be cleaned out before final assembly to avoid internal damage.

DIY Installation Guide

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Community Verification

1
user verified this swap
By cauQazn via Club RSX
Added 1 day ago

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Sources & References

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