USDM SVX...Install VDT JDM transmission?
 

Has anyone experience w/ installing Japanese VDT automatic into a US car? The simple form is: Are the TCU computer pin outs compatible and as anyone just plugged a VDT transmission into a US TCU to see if it shifts and drives correctly?

From reading I know we have to change the rear diff to a 3.7 ratio (Nissan has the ring and pinion still available new, worst case). I also read that the speed sensor has been moved on some of the later transmissions, but I understand that the Japanese VDT transmission and the non-VDT SVX units are the same in all respects except for the rear transfer case area and possibly the pinion drive shaft.

I am assuming the transmission electronic shift control should be the same. Has this been confirmed? Can anyone provide a wiring diagram for the Japanese VDT TCU? With this information I can figure it out. My assumption is only difference in the TCU logic is a throttle/speed bases map for the VDT instead of, or in addition to a wheel slip based map of the front drive/rear take up clutch version.

My idea is that if the rest of the transmission control is compatible between a non-VDT and a VDT transmission, so that it shifts and drives OK, then VDT can be controlled with a stand alone unit as used with Group N WRX rally cars 1999-2004 if a person wanted active VDT.

We have a VDT transmission and would like to use it. Any technical information would be a big help, as I do not have ready access to VDT technical information.

==m==
mshields@spdusa.com

VTD Conversion.
 

Depends on what model car and year the trans came from. The 92-97 model from Jap, UK, Australia, can all be fitted to the US model, as long as the TCU for the same model trans is fitted also.

The later models and TCU are not so compatible.

Harvey.;)

in the short run...use us tcu?
 

The JDM transmission has the speed sensors in the same location as the US one. We have installed the JDM box into the car. Trying to locate a Hitachi 3.7 R160 ring and pinion. None of the US Subaru had 3.7 that I am aware of. Will try to get a 3.7 ring and pinion from NISMO here in Los Angeles or get one from a salvage yard.

Will drive the car to see how it shifts. The VDT solinoid is not critical for day to day driving, if we can get the car to just drive. Paid $200 for the JDM box, so it is worth the experement.

Can anyone help locate a JDM TCU (early style)? We wire STI drivetrains into GC Impreza chassis all the time, so we just need parts and a diagram!

Thanks in advance to all!
==m==
Mike

The US TCU will run the box, but the line to the C solenoid needs to be inverted, as it is the oppersit to the VTD signal.
No signal = no clutch action, on VTD.
No signal = full clutch action on Transfer.

This will run it, but it won't be the same as the VTD TCU.

Harvey.;)

Super- Anyone have JDM TCU pin outs?
 

Thanks for the re-assurance! If someone can provide 1) wiring for JDM and hopefully, 2) a line on a JDM TMC, I will take the time to document any needed changes we find as against the USDM TMC wiring.

Regards,
==m==
Mike

The JDM wiring looks to be the same as the USA wiring. At least, all the colours match up against the diagram. But as Harvey said, you'll need a JDM TCU to make it work properly.

Barry, an owner in the UK, had an SVX imported from America. When the gearbox failed he had it replaced with a UK VTD gearbox and TCU. IIRC he later sold the car to a guy in Germany.

Thanks Phil, thought you would be able to say which one is the go. The only problem with the JDM TCU is the speed limiter.

Harvey.;)

No. The speed limiter in the the ECU.

- and it's easily bypassed anyway :D