[b3lha]

Originally Posted by oab_au

Phil to understand why this is so, you need to understand why Subaru did it in the first place.

When this transmission was used in the Sporty WRX and RS Turbo, the change was fast and solid, just what you would expect of a Sporty car. When the SVX was designed it was aimed at the higher end of the Luxury Grand Touring market. The same fast solid change did not suit this market, so they programmed the TCU to lower the line pressure during the change, to remove the solid engagement.

Because the reduced pressure would allow the clutch and band to do a lot of slipping to smooth the change, they turned the Engine torque down to prevent excessive wear. The result was that silky smooth gear change that suited the Luxury profile that they wanted, but at the expense of clutch and band wear.

As the Quick Change prevents the line pressure from being lowered during the change, there is no need to reduce the engine torque. So it converts the gear change to the same fast solid shift, as we had with the Sporty models.

Maybe that's true. I think that firming up the shifts by recalibration of the line pressure is probably a very good idea and might help to extend the life of the transmission.

But the less torque you apply to the clutches, the less they will slip and the longer they will last. It seems to me that reducing the torque during a shift must a good thing for gearbox longevity. Conversely, disabling the torque-cut signal must surely subject the clutches to more torque, more slip and more wear than leaving it alone.

I accept that the primary goal of the QS device is performance, rather than gearbox longevity. But it's stretching things a bit far to claim that it will definitely make the transmission last longer. Maybe in a few years time, when people have done 80000+ miles with a QC, we'll be able to look at the failure stats and say whether it is better or worse. But right now it's just speculation either way.