Disco 2 Stall speed monitoring

has anyone had a stall speed monitoring fault on your auto box (TD5)? i have done a stall test and that passed and using my diagnostic machine the output shaft speed shaft speed doesn't change as i increase road speed. Is there an easy was to measure the resistance in the sensor without removing the sump?

also what should the resistance be and what is the part number for the sensor?

You can measure the sensor's resistance at the EAT ECU's plug across pins 14 - 42 but i dont know what value to expect, p/n is STC4444

I've tested the pins for and got a reading so I went ahead with a new sensor, unfortunately the same code comes back, any idea what else it could be?

Wiring or ECU fault

After tests I've came to the conclusion that's it's the auto box ecu, is it possible to use a ecu from a newer auto or does it need the same numbers

Any Td5 ECU should work, even a V8 one but with different shift points

I've done all the tests possible so i think im going to strip the box. There is a slight vibration so maybe a bearing has 'gone' wearing away the teeth on the reluctor.
Does anyone have the workshop manual including disassembly?