Vehicle Speed Sensor is the one that your speedometer cable connects to (If you have the mechanical speedometer).
That is the one that is hard to get to.......you have to go by feel.
It is above a catalytic converter, so you have to let that cool down before working.
The speedometer cable is in 2 parts (at least on my '96), the connection is below the flex hose that goes from the air filter box to the throttle body.
The Turbin Shaft Sensor, TSS, is located on the driver's side end of the transaxle.....near where the driver's side shaft comes out.
It measures the speed of the shaft that comes out of the torque converter and goes into the gear select part of the transmission........often called "Intermediate" shaft.
At this point.....I would recommend trying to read the codes, the VSS and TSS should trigger a code if they are defective.
It can get expensive pretty fast changing parts and not have them be the problem.
It is also possible.....though I hope not.....that the problem will be internal to the transmission and be expensive to have repaired, the sooner you find out, the better.
ABS sensors..... At the end of each shaft going to each wheel.....you will find a "Gear".
That gear is the exciter ring.......and you will find the sensor located next to that.
The each time a "tooth" of the gear passes the sensor, it creates a magnetic pulse.....which the sensor turns into a electrical signal.
The computer measures the pulses from each wheel sensor to determine how fast each wheel is turning as compared to the other wheels......then the ABS system can determine if one or more wheels are in a skid.....and pulse the brake for that wheel.
Here is a link to a picture of the front suspension on my '96 Windstar that shows the ABS sensor and exciter ring.
http://rides.webshots.com/photo/2030...11220610romxdY