Automatic Transmission Fluid Change in Prius Gen 2

[Reda Mohamed]

Hi guys,

Regarding the automatic transmission fluid change for a high mileage Toyota Prius Gen 2;

* Is there a harm not to change because I have heared if you change you will harm your gear?

* Is there a benefit interms of improving the mileage of the car , maitain the gear and etc...?

Any ideas please?

Thanks in advance.

[FROSTYBALLS]

Moved to the Prius club.

[TonyHSD]

YouTube and priuschat us forum may have useful information about Prius gen 2 and transmission fluid change. Best to double check these two places before make any decisions. I personally change my transmission fluid every 60 k miles in gen 3 hybrid. 👍

[Red_Corolla]

It's true with conventional automatics that it's often better to let sleeping dogs lie if they've never been maintained before. That's because, sometimes, the old friction material suspended in the fluid is the only thing keeping them going. Some people go to the other extreme and 'flush' the transmission, either using a pump or by draining and refilling repeatedly until every drop of old fluid has been replaced. Again, this is not the best thing, because that little bit of old fluid that remains actually helps to slow down the wear and tear on the friction materials, so it's a balancing act and the best maintenance is a simple drain+refill at sensible intervals.

The Toyota hybrid gearbox is far more straightforward, it only has gears inside and doesn't rely on friction surfaces to transfer the power. They have more in common with a differential than a conventional automatic transmission, and it should be quite safe to replace the fluid even if it's never been done before.

[TonyHSD]

Gen 2 has a belt(chain) that transfers the torque from the power split device to the differential, I never had one and I never worked on therefore can’t say for sure but I agree with Stuart on that, change drain and refill should be safe 👍

Here is a useful video 

 

[Saxmaniac]

Car care nut channel is a good source of info about meticulous maintenance, he advises 60k but the benefit is really from removing metal particles and any other contaminants, though there's no ratio swapping or clutches in there