Complete overhaul kit for the Jatco JR405E / RC4A-EL four-speed: frictions, steels, gaskets and seals for the 2004-2005 Mazda RX-8 automatic.
Early Mazda RX-8 automatics use a Jatco four-speed that Mazda catalogs as the RC4A-EL and Jatco calls the JR405E. When a 2004 or 2005 RX-8 starts flaring on the 2-3 shift, takes a long time to engage drive on a cold morning, or shows dark fluid with lining in it, the clutches and seals have reached the end. This master kit carries the full set of soft parts for a bench overhaul: the gasket and seal set, the friction plates, the steel plates, the O-rings and the metal-clad seals you need once the case is apart.
The JR405E is a rear-wheel-drive, step-type four-speed with a separate bellhousing, case and extension housing. Transmission Digest describes it as the rear-drive twin of the second-design Subaru four-speed. There is no band and no overrun clutch, so every shift is clutch-to-clutch. A single low clutch handles forward drive, the reverse and high clutches share a compact drum with the high piston riding inside the reverse piston, and a 2-4 brake and a low/reverse brake hold the planetary members, with a low sprag for first gear. A gear-type pump supplies pressure, and the valve body uses six solenoids and three pressure switches. Because shift timing depends entirely on how fast each clutch fills and releases, worn frictions or leaking piston seals show up quickly as flares and tie-ups. This kit renews every friction, steel and seal in those circuits at once.
Check the fluid level and condition first. Then scan for codes and watch input and output speed on live data. The JR405E uses external input and output speed sensors, so a sensor or wiring fault can look like a slip and should be ruled out. If the ratio slips under load in one gear and the fluid smells burnt, the clutches are worn. Our transmission slipping diagnosis guide covers the test drive, and the ATF color and smell chart helps you read the fluid. Weigh the job against a replacement unit with our rebuild vs replacement cost guide.
This kit is listed for the JR405E / RC4A-EL, specifically the 2004-2005 Mazda RX-8 1.3L automatic. The same Jatco family also appears in markets outside the US, including the Isuzu D-Max and Suzuki Vitara. Later RX-8 automatics use a six-speed transmission that this kit does not fit. Confirm that your car has the four-speed automatic and check the code on the case tag, or send us your year and VIN.
| Transmission | JR405E (Jatco 4-speed), also RC4A-EL |
| Replaces | JR405E, RC4A-EL |
| Fits | Mazda RX-8 1.3L 2004-2005; Mazda Bongo 1.8L / 2.0L 2004-2005; Isuzu D-Max and Trooper diesel |
| Kit Contents | Overhaul gasket and seal kit, friction plate kit, steel plate kit |
| Ships | From the USA |
Yes. JR405E is the Jatco name and RC4A-EL is the Mazda designation for the same four-speed automatic.
No. It is listed for the 2004-2005 RX-8 four-speed automatic. Later RX-8 automatics use a six-speed. Check your case tag or send us your VIN.
No. Transmission Digest notes the design has no band and no overrun clutch, so every shift is clutch-to-clutch. That puts the focus on the clutch clearances and piston seals this kit replaces.
Hard parts such as drums, the pump, bushings, planetary sets, solenoids and the torque converter. Inspect those during teardown and replace any that are worn.
Use the automatic transmission fluid listed in your RX-8 owner's manual, and check the level with the fluid at operating temperature.
