Thoughts on the Auto Transmission

[Nomake Wan]

Well I've been doing some thinking here and there... and there and here... so I figured I'd toss my thoughts to the sharks and see who bites.

As far as my research can tell, the US did not get a VTD Automatic transmission until 2001. And all the VTD transmissions from 2001 onward have a 45/55 split. Whereas the Japanese had a VTD transmission starting in 1992 (with our beloved SVX!) which until 2001 had a 35/65 power split (except for the Forester which had 45/55; the source for the 2001 transmission probably).

This is where I ask people to poke holes in what I've said. I can only search so far on the web, so my knowledge is limited to what information I can find. There is a lot of information on Japanese websites about Japanese specifications, but I have had little to no luck finding a definitive source for information on American-spec automatic transmissions. So I ask if anyone knows more about the US! Specifically, was 2001 really the first year for the VTD in the US? Do they really all have a 45/55 split?

And then, the final question. Why is it that we can't put one of the US VTD transmissions into the SVX? I noticed that for automatic transmission swaps, the cutoff year is 1998. What happened to the transmission in 1999+ to make it incompatible with the SVX?

In case you haven't noticed, I love learning new things about Subarus. Would love to get any insight I can.

[subster]

hmm...

I assume VTD means Variable Torque Distribution.
All Wheel Drive VS. 4WD in my mind means that AWD is active while 4WD is static.

VTD would be that active part, it varies the torque between the front and rear wheels.

My Auto 2002 OB VDC Wagon is 50/50 until wheel slip.
It varies torque.

My old Auto 96 Legacy L Wagon I believe was 70/30
It varied torque.

My Auto 2000 RS also varies torque. Though I don't know the initial distribution.

The SVX's are like 90/10 right?
They also vary torque.

As far as not using a newer auto, I don't have the answer for that but I would guess different bell housing or something.

[Nomake Wan]

VTD does mean Variable Torque Distribution, but it isn't as literal as you assume it is.

The older systems (90-2001 in the US) are called ACT-4 or "Active AWD" systems. They are essentially FWD (90/10 split) until a loss of traction, then they transition to 50/50.

Whereas VTD-4WD systems are rear-wheel biased (the Japanese-spec is 35/65) until minimal traction, then transition to 50/50.

EDIT: Your 2002 Wagon is VTD as well (VTD is part of VDC). So I believe it is actually 45/55 split.

[Tim]

The problem with the 98.5+ years are is that the TCU wiring is different. IT needs to be completely rewired to work.