No Shifting After 3Rd Gear

[RyanW]

Hello,

I recently noticed that My Corolla 121 Doesn't shift to its 4th Gear and it keeps on going on the 3rd gear and makes a "Hum" noise from the vehicle.

Did check the Transmission oil and they seems to be fine.

Any Comments????

[bogzy]

have you checked if O/D is off ?

[harshansenadhir]

Does it shifts other gears normally and only does gets stuck in the 3rd ? or no shifts at all and stuck always in 3rd gear?

if it's the first, simplest thing to check is the O/D switch and the connectors at the gear lever end and gearbox end. If it's stuck in the 3rd gear always, it's fail safe mode in most auto gearboxes. Time for an expert intervention with detail diagnose

[RyanW]

O/D is off....

And the 1st, 2nd and 3rd Gears Shift smoothly.... After 3rd Gear its stucked... and when i accelarate it gives a hum noise as well..

[terrabytetango]

Apart from the OD switch, this issue has a little ambiguity to it. Firstly, at what speeds do you drive? If you're touching speeds of 90km/h and the engine is turning over at 3000rpm then yes your car has a problem. But if you're simply not going fast enough for it to shift into 4th, well then press the right pedal a little harder

Edit: And every car makes a "hum" noise when in motion, you'll have to be more specific.

Edited April 17, 2012 by terrabytetango

[RyanW]

well there was no "hum" noise before... and yes i can drive more than 100 km/h upwards with the rpm around 2500-3000 (but not shifting to the 4th)...

[harshansenadhir]

You said O/D is off. Why don't you switch it on (disappear the O/D off light from the dash) and see.

[RyanW]

well O/D is not displaying in the dashboard...

and yes, tried with the O/D on and O/D off... nothing changes...

[terrabytetango]

The dashboard indicator will only display "O/D Off". The indicator will stay lit only as long as the engine is running. When you start your car the next time, it will be off because O/D is always enabled by default. But if you're in limp mode, your check engine light and the O/D off light should be lit or flashing. One thing you can try is to press the OD button while maintaining 80-90 kmh, if you're already in 4th then you should downshift to 3rd and vice versa. Don't go beyond those speeds since a downshift will cause unnecessary overrun of the engine.

Edited April 17, 2012 by terrabytetango

[RyanW]

yes i understand the thing about the "O/D" on and Off...

And there are no Check engine indications flashing or indicating..

[The Stig]

yes i understand the thing about the "O/D" on and Off...

I dont think you do, OD is the 4th gear. It should be always on, no reason to turn it off unless say you are going downhill or need engine braking. Turn OD on and give it another go

[poscher]

It could be that your gearbox oil is overheated, this is caused due to a few reasons, but most commonly due to the Radiator Failure and bad gearbox oil.

[NZer]

I say do a oil change and see. If you have tampered with the Thermostat in the car, will also cause the OD not to engage. The vehicle has to come to proper operating temperature before the OD will start to work. If the heat does not reach normal midway mark you will not get OD. Also it could be a faulty switch. It wont be a serious issue as all other gears work. Also when you check the oil level make sure u start it and then put it in neutral and then check. Good luck.

[Az]

I say do a oil change and see. If you have tampered with the Thermostat in the car, will also cause the OD not to engage. The vehicle has to come to proper operating temperature before the OD will start to work. If the heat does not reach normal midway mark you will not get OD. Also it could be a faulty switch. It wont be a serious issue as all other gears work. Also when you check the oil level make sure u start it and then put it in neutral and then check. Good luck.

Are you saying that the car will not shift to 4th, however high the RPM or speed, until the engine reaches proper operating temperature?!

[NZer]

Yup thats exactly how it works. As a safety precaution the Over Drive is controlled by heat of the water in the radiator. When the water is cold and the vehicle hasnt reached operating temperature the Over Drive will not Engage. This will delay the time the over drive kicks in (if the thermostat) is missing or will completely stop it from getting into over drive if the temperature hasnt reach mid way.

[NPP]

well there was no "hum" noise before... and yes i can drive more than 100 km/h upwards with the rpm around 2500-3000 (but not shifting to the 4th)...

100 km/h at 2500-3000rpm sounds it's already in 4th gear to me. ....

[nano31]

If what you feeling is true,I feel it is something to do with your automatic gearbox modulator