I have a 1987 740 Turbo. The original rear axle and diff were replaced due to a leak and damaged bearings. The original diff had a 3.54 ratio. The previous owner replaced the diff with what he though was an '87 diff. Turns out it has a 3.73 ratio and the speed sensor does not work (goes to 100+km/hr in first). I think that the new axle and diff came from a newer model with ABS.

I still have the original speed sensor and I am going to replace it. Does anyone know the number or teeth on the original '87 sender gear? I have been told that the number of teeth was probably 48...also told the number on the 'new' diff is probably 96. I can check the number on the new sender gear when I put the original sensor in.

Does the speed sensor output a voltage or a pulse? If it is a voltage does anyone know what the voltage should be (as a function of speed) for an '87 740.

If the ratio of old teeth/new teeth = 48/96 (or 1/2) can I simply use a voltage divider circuit (1 resistor in line with the white-green wire and 1 resistor in parallel between the white-green and brown wire) right off of the sensor wires? Would this correct my problem??

Any suggestions would help.