96 Taurus Speedo and Trans malf replaced the VSS

run the fault but all you describe is operated from the VSS sensor ( vehicle speed sensor)
it tells the cruise control the vehicle speed , tells the TCM the vehicle speed so that ratios can be changed, activates the speedo,and will report with a check engine light to report a transmission problem
run the fault codes first

a real DTC code.
17 , 94 Accord
the means VSS is dead, vehical speed sensor (miles per hour)
so , that begs the question is the speedometer dead or odometer
dead or acting funny IN ANY WAY?
is this an A/T Car or M/T car, both have VSS, so... cant answer.
Auto or stick, ill pretend, AUTO.
VSS moves all over the place, in all cars. all models and all years.
on this car, its odd.
quote FSM:
Accords and Preludes use an external sensor mounted on top of the power steering speed sensor in the engine compartment. The power steering speed sensor is gear-driven and controls the steering boost in relation to the speed of the vehicle. An electric pulser unit is mounted on top of this unit and is coupled to it by a small shaft. The motion from the lower unit is transferred to the upper unit; the resultant electrical signal is sent to the appropriate control units.

most cars old use the speedometer VSS sensor inside
on newer cars 1996 (on avg) the sensor is on the tail shaft. and in speedo.
on very new cars there are 3 VSS.... (dont ask)

on my 96 car, the tranny VSS can fail and then FALL back to the
SPEEDO head. and tranny still shifts but is funky,
the FSM covers all this, i recommend getting one, to understand
how it all works.

your car has and electronic speedometer
the VSS orange wire , sends speed data to the PCM, TCM, cruise.
the PCM then sets the speedo dial, and uses this info to run TCM
controls to the transmission.
your orange wire signal is dead or flaky.

the vss runs off a gear in your transmission.

The trans filter has nothing to do with shifting,
you surely are knowlegeable enough to know that

If you were out of money, you would be riding a bicycle
& eating at a soup kitchen

Take it to a trans repair shop

try having the VSS (vehicle speed sensor ) replaced, this is where all the data for the powertrain control module (PCM), made mine shife perfect and made the speedo and cruise work better too

93 and up are shifted by the computer. If the VSS is bad, it does not know you are moving. The speedo is on the driver side of the tail houseing to the trans.

If you do replace it and nothing happens, you will need to diagnos the signal to the computer or the computer itself. However it is more likely that it is the speedo itself.

Hope this helps.

speed sensor needs replaced

you'll need to get it diagn., it can be as simple as a "VSS" sensor, or a transmission, check the fluid and if BURNT, your looking at a trans.....GL....

have the fault codes read
the speedo gets its signal from the VSS ( vehicle speed sensor) and that sensor also reports to the transmission control module
So check for a problem in that area

inspect the throttle valve control rod. there could be a small part that has worn out, usually made of plastic and the size of a dime. if this part is missing out worn out it will make the trans shift at the wrong time. it happened to my lincoln once and i thought the trans was going out.