Is it the Transmission ? (Transman, Pl help!)


#1

Our car (1997 Mazda protege; 4sp Auto; 96K miles) off late seems to be giving what may seem like a transmission issue. Usually it shifts 3 times and then around 45-50mph , seems to go to overdrive (based on odometer shifts). But last several weeks it either hesitates to go into overdrive, or doesnt go at all. It strangely happens more often in some conditions : evening/night time (cars sitting for the day); cool/wet days. Car is driven mostly on highways.



So the question is, is this a reason to worry about the transmission, or could it be some sensor not functioning properly ?



thanks


#2

I’ll chime in until Transman618 posts. On most modern cars overdrive is locked out electronically until the ECM determines that the engine is warm enough. It is a strategy to lower warmup emissions.

So make sure that the engine is warming up correctly, i.e. the thermostat is not stuck open. Then have the Engine Coolant Sensor checked for calibration accuracy. It could be telling the ECM that the engine is not warmed up. This would also hurt your gas mileage.

Hope that helps.


#3

What you are describing is TCC (Torque Converter Clutch) lockup. You say it shifts 3 times, well, that would be:

1: 1st to 2nd
2: 2nd to 3rd and
3: 3rd to O/D

Now, you are saying at 45-50 it seems to shift again. This last shift is actually TCC lockup. If you are having issues with TCC lockup (Falling in and out of lockup) the problem could be electronic or hydraulic. To diagnose this, a scanner is needed to monitor lockup. This is where a trans shop comes in. Unless you have a scanner (Not a code reader) and know how to diagnose the TCC lockup, I would let a trans shop do a diagnostic… Does the problem go away if you cycle the ignition switch off then back on again??

transman


#4

thanks, for your response no actually, it does not always go away if I switch off the engine. it seems pretty random to me (though affected a little by temperature)


#5

yeah, i’ll have that checked. but wouldnt that mean that once the car is warmed up “enough” the lock up should not hold (unless it stays on until you turn on the engine.


#6

Possible TPS issue causing the TCC to fall in and out of lockup. I would get it checked out by a reputable trans shop first before blaming the transmission and thinking the worst.

transman


#7

By the time it shifts 3 times it is in overdrive. Any shift that you feel after that is the converter locking up. Now I know that dosen’t answer your question but thot you should know how it works.