The Dakota Digital SGI-5 won't recognized the signal. It wants 0 to 12vdc or 0 to 5vdc. If you are getting somewhere with a signal conditioner that would be the best way of doing it hands down. But I'm still looking at alternative approaches as well.
If you can do this, we should probably find out the true ratio of the NV245, they state 2.72. Just like 3.73 gears are really (41/11) or 3.7272727......
What I am finding out is all wheel tone rings are 48 teeth per rev. If the transfercase is truely 2.72 the conditioner would need to be 1/2.72 of 48.