OK I found this on a different site.
1. Your ABS/ VSS can be removed and cleaned with just a clean rag, no need for wd-40 or any other solvent, also carefully clean out the hole on top of the differential, lift the vehicle (place in neutral) and check the sprocket wheel inside the pumpkin for possible missing teeth or to see if it is loose.
2. The VSS (part # F85F-9E731-AA) can also be tested with an ohms meter, it should measure ~1.9 K-ohm or higher (lower than 1.9 requires replacement).
3. The VSS is a hall-effect sensor, connect a volt meter to the sensor connector and wave a piece of metal (pair of pliers or flat metal) about a half inch away from the sensor, and you will consistently see a variation in voltage, if no movement on the volt meter is observed, replace the sensor.
4. You also have the two front wheel ABS sensors, try cleaning them first, and carefully reinstalling them.
5. When the VSS sensor is malfunctioning, the PCM may try to get input from the TSS (turbine speed sensor, top of the transmission), and as it turns out, the same return wire is used by the OSS (output speed sensor, tail end of transmission), check these two sensors also, clean them and test them (1.10 K-ohm or higher). These are also Hall Effect sensors, so check for voltage as described in paragraph 3 above.
6. Pay attention to see if your ABS light blinks when you start the vehicle, just before it stays solid. If this is happening, count the number of blinks, as this is actually a code and the blinking means the vehicle is trying to communicate with you.
7. Last, if nothing above corrected the problem, I would start tracing RFI (radio frequency interference), one sure area is usually your fuel pump (wires running along side VSS wiring. ABS/VSS wiring is routed directly to the ABS module.
I hope this information works for you.
I checked my old sensor with my digital meterset at 200k. Is that the correct setting?
Old sensor 1.1 ohms resistance
New sensor 2.0 resistance
I set the meter to 20v dc and passed a wrench infron of the new sensor and the reeding went from 0.00 to 0.03.
SO does that sound like the new sensor is good?
This sensor on the trans you are talking about. Is that the sensor on the pass side top rear? Little round sensor with the ball in the end? I have one on the trans and one on the transfer case. Is that what you are talking about? Whats that called? Also where is the abs module on an early 99 with rear abs only?