speedometer sensor the one inside the tranny

[MR22007]

i have a 93 mr2 turbo 5-speed
102500 miles O.G

when the out side temp is 90 or above speed sensor work just fine.
but when the out side temp is below 90 it doesn't work right
i could be going 40 mph but my speedometer is reading that im only going 30 mph

does my check engine come on? no
could it be im running the wrong tranny oil.
O.E.M oil is 75w90
could it be the older the tranny the low the wight i need?
or could it be i have a bad sensor?
BUT i have had a toyota service rep tell me it looks to just fine
he all so told me that some time the gear on the senor get eatin up thats what make them go bad.

[toyomoho]

Typically the sensor has a plastic drive gear that engages a gear in the trans. Did the dealer pull the sensor and look at this gear? They can also check the sensor electrical output.

As the problem seems to vary with air temp you might have an electrical connection problem, perhaps in the speedo console. Or the speedometer itself.

There may be a trouble code for loss of sensor signal to ECU. But the CEL may not come on if the signal is just off a little.

The sensor is typically sold without the gear, thus check both the gear and sensor signal output. The sensors are not cheap thus make sure it really is the problem.

[MR22007]

Now that it cold it really doesn't work now. Now also my tachometer doesn't work very well even when I warm up my car.
Speedometer reads 20mph but I thank I'm going 60mph.
Its 2010 now. .... Any help out there

[MR2Jedi]

Did you ever replace the speed sensor on your tranny?

[talfshow22]

would my speedometer not working throw an engine code??

[MR2Jedi]

No