VSS help needed

I'm interrested in installing the stock VSS on the drive shaft (with magnets or a ring gear of some sort) on my 2004 PD conversion with Toyota trans. I know the ECU wants a number that will be very close to the stock number of pulses for the cruise to work. I found this out the hard way as the first PD 5th gear upgrade guy and the cruise wouldn't work.
Does anyone know the exact count needed? how many teeth on the gear the VSS looks at? is it on the output/ final drive portion of the trans?
Thanks for any help. Hal

What Toyota trans is it?

I was able to get a Toyota 3 wire sensor (puts out a 0 -12V square wave) with 4 pulses per driveshaft revolution.

I have a W55 from a 1988 pckup. I know the VW ECU is quite sensitive as to counts on the PD motors. Just putting the overdrive 5th gear in is enough to kill the cruise My Bentley doesn't show much detail. I may have to dissasemble the diff. to check it out.