Thread: Td5 auto box overheating in 4th but not 3rd

Hi. Do you have a gauge to monitor the transmisssion oil temperature or how do you know it's too hot? If the oil temperature switch is working but doesnt come on while driving and you have bigger than standard dimension tyres then IMO it's quite normal for the box to get hot... you can check the switch by pointing a laser thermometer to it and blow on it with heat gun untill it exceeds 120*C then the warning should come on so as long as the warning is off while driving you should be OK, though if the warning comes on much below 120*C the switch is ''tired" and you need a new one

Thanks mate. I knew it was hot as I could smell gear oil when I stopped. Since bought a thermometer and looks like it was around 110. So hopefully no lasting damage. Although I suspect it went higher than this initially. So I checked fluid level and managed to get about another 700ml in. So feeling pretty stupid now. I realise I should drop the oil and have enough to do so but going to give it another go now and see how she goes.

Didn't have a warning light but will be checking that when I get back. Do you know where the sensor is? Surely purposely overheating gearbox is a bad idea. Or do you this with engine off? Thanks again.

The temp switch is screwed into the bottom of the cooler on the RH side, you have to heat up only the switch's body to check it with ignition on

When the transmission oil cooler gets stuck (which is a common root cause of overheating transmission), there is no flow into it, so it remains cool together with the temperature switch even when the transmission itself is overheating. Learned the hard way unfortunately.

Are you towing ? Is the country hilly or flat.
How heavy is the vehicle ?
Whats the air temperature ?

Ian
Bittern

Hi all,

Thanks for responses. Not towing but fully loaded with roof rack. Some hills but not too big. It is windy tho.

I thought it was fixed after top up and removing maf but alas no. Was fine for a week reaching 105 degrees max. But last couple of days it has been going north of 140 even though I have been taking it easy. I'm going to limp home in 3rd gear so 80 kmh max and figure it out when I'm home. In 3rd it's sitting happily at 80 degrees. 4th up to 90kmh and it's overheating.

Cheers.

slipping torque converter clutch will cause overheating, being in 3rd at highway speed the converter will be at fluid lock up ( around 2800 rpm ) so will run cooler, shouldn't smell of gear oil though