Powershift, FORScan & GISS

[AlCan]

Hi Guys,

As you'll know, I've been learning about the first two items, now up to the third...

This has been (still is) a real puzzle to me, and I'm hoping someone can solve it for me - Mondaveo, with all your Speed Sensor / FORScan experience, can you shed any light?

The 6DCT450 has (as we all know) two clutches and two input shafts.

As someone who like to understand things, it makes complete sense that there should be a Speed Sensor for each input shaft. There's a third Speed Sensor for the Engine RPM which it reads off the outer clutch drum. That's the one that connects internally to the TCM by a plug and wires near the main Circular Connector on the front of the box. (Diagram pg 42)

I have a copy of the ATSG Powershift training manual(?) from 2012 which explains a lot of things about the transmission, but sadly, not all of it. And it has a few mistakes and inconsistencies.

One inconsistency surrounds the Input Shaft Speed Sensors. On pg 41, it clearly mentions these three speed sensors: Engine and Odd & Even Input Shafts.

The input shaft speed sensors must also operate by Hall Effect, and read gear teeth on the relevant shafts.

The lower half of pg 42 shows all the sensors stalks that protrude from the TCM into the transmission, with arrowed descriptions. One says: "Reads Input Shaft 2 Speed". All Good.

Another says: "Reads Input Shaft 1 Speed via Output Shaft 2". That one really had me guessing - how can it do that?

The diagram on pg 30 is even more confusing: "Output Shaft 2 Speed Sensor ... Hole". What use is that? In effect, since both output shafts are geared to the differential ring gear, it's really a vehicle speed sensor.

Today, finally, I figured it out. It's not quite clear, but what is must mean is: "Input Shaft 1 Speed Sensor Hole" and "Reads Input Shaft 1 Speed via Gear 5 (idler) on Output Shaft 2".

To me, that makes perfect sense (ratio around 1:1 - clever) as there has to be a Speed Sensor for each input shaft, since it's key to clutch control.

[FWIW, the Mitsubishi 470 redesigned box info is much clearer, and there are two clearly identified input shaft speed sensors shown.]

Which brings me to my real question:

Is there a second PID for the other speed sensor? Or are both speeds somehow kludged together into the one GISS? To me, that's really no use at all but maybe that's it, or maybe the FORScan guys have missed it.

Any thoughts and comments greatly appreciated.