Thread: TD5 Auto Temp Fluctuating

Hi, a fluctuation is normal, what do you mean by "dramatically", what temps have you read? ...cos there is a thermostrat on the cooling system.

Temps in the transmission fluctuate as the torque converter locks & unlocks. Mine will drop from 80/90 deg to 60 deg after 2 or 3 km above 80 km/h with the torque converter locked. My transmission & engine run cooler at 60 km/h in 3rd gear with the torque converter locked than in 4th gear with the torque converter unlocked. Problem is that you have to get up to 70 km/h in 3rd gear to lock the torque converter.

...sorry, just realised that it's about transmission cooling not engine cooling... when it comes about automatic transmission i'm too dumb to help you, what i know is that the engine will run cooler at 60 in 3'rd than in 4'th on a short run cos the rpm is higher and the viscous fan pulls harder...i observed that not once with tester on live data

I'm not sure anyone other than ZF will know exact numbers,, but you've hit the reason on the head, when locked up the oil is "still" and assumes the case temp,, when unlocked its being moved about quite viciously and heats up accordingly.

Anyone that has some actual knowledge of this want a go now?

Temp is being read by TM4 with the sensor on the outlet hose from TC.


The temp generally rises on inclines and cools on the flat and downhill.


The problem is that it also rises above 115 on long or steep inclines (coolant temp 94-96 on Nano, EGT post turbo 350-450) but temp cycles between 54 and 90 without any changes. Locking it in 3rd doesn't seem to help.


Ive just hooked up the TM4 so I am not aware of what the long term figures have been.

Originally Posted by Brad110

Temp is being read by TM4 with the sensor on the outlet hose from TC.


The temp generally rises on inclines and cools on the flat and downhill.


The problem is that it also rises above 115 on long or steep inclines (coolant temp 94-96 on Nano, EGT post turbo 350-450) but temp cycles between 54 and 90 without any changes. Locking it in 3rd doesn't seem to help.


Ive just hooked up the TM4 so I am not aware of what the long term figures have been.

To go a bit offtopic here. But how fast and what sort of rpms are you doing to get those egt temps uphill?

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Backed off to keep them low. They can easily reach 500+ on a long incline or if I put the boot in. These readings are post turbo therefore 100 deg lower than in manifold.