I installed it in the Tcase, I had to, cause I swapped the 8.8 out for a D60. I disabled my abs a while back cause it didn't work very well with the locker in the 8.8.

 

So what conversion constant are you using? The VSS only produces 6 pulses per speedo cable rev, which is hard to convert to wheel revs but it's a lot less than the 108/wheel rev produced by the ABS sensor.

 

Sorry it has taken so long to get back. But here is what I based my conversion on and cal numbers.

The VSS as well as the ABS all count ppm, 8000ppm I believe. The Vss counts 6 pulses per rev on the cable, now with the the driveshaft rev being higher then the cable, due to the drive and driven gears, the ratio is 2.14:1. This would change with what drive/driven gears you have in the tranny/tcase. Now at the other end the of the drive shaft I have 3.55:1 ratio with 108 tooth ring. I had to figure out what size ring I would use for calculations to maintain the same ratio from drive shaft revs to ring revs based on 34" tires.

What I did was took the ring 108 divide by the r&p ratio 3.55 and got 30.4, then took a false ring number 66 and divided by the speedo reduction 2.14 and got 30.8. Almost dead on from driveshaft to axle/cable. Now 66 puts me out of limits for cal numbers so I had to use 70 as this put me up to 524cal.

In effect I lied to the psom and told it I was running 50" tires based on the 108 tooth ring. You wont be able to do this if you used anything higher than the 35" tire or lower gear ratio, as you will run into speedo error that won't be able to be corrected. Now as compared to the gps at 50km +/-2km and at 100km +6/7km

Check out these sites

http://www.magsensors.com/ cable to electronic
http://www.abbott-tach.com/cablex.htm electronic to cable