If you have access to Techstream or 3rd party device apparently there is an estimated ATF thermal degradation parameter that can be accessed.

 

That is very interesting. I wonder if the dealership will acknowledge it

 

Surely they will ....outside of warranty ;-)

 

There is a very detailed process of changing AT fluid but thought this was an interesting tip if someone performed job without a Techstream. They are very adamant about fluid being between 115-126 degrees F when filled to top of fill hole. Just a method to monitor AT temps during service if you don't have Techstream.




On OBD connector connect the following terminals

 

Why not just wait for transmission to cool down to same as outside temp, drain it, measure what you drained, replace with same quantity of new fluid?. It might not be 100% accurate, but IMO it's good enough. The drive train on these trucks survives with road side maintenance in 3rd world countries.

 

That's how I would normally change it too... there is also that transmission cooler line thermostat cutoff step that you are supposed to do as well. Perhaps though that is related if you were changing hot fluid and wouldn't be applicable to a cold drain and replace.





•••On a side note anyone ever experienced the slow speed surge described in this old thread?

https://www.clublexus.com/forums/gx-...ion-surge.html

I've felt a couple times at really slow speed in a parking lot or crawling in traffic. I've still got a little less than a year on powertrain so will keep an eye on it. Not

 

I think the "ATF thermal degradation parameter" may not be present on the '10-'13 models. I've looked around in all the data lists and nowhere to be found. Perhaps someone with a '14+ can confirm?

 

On the cars I previously owned there were always some method to check if the ATF level was correct or not. On the GX it looks utterly complicated. When I do a partial ATF change I will go with measuring the amount that comes out and fill back the exact same amount.

 

I dont have the manual handy but is 50k the recommended interval for changing the ATF ? I dont really follow the purpose of the degradation warning, is this sort of an internal maintenance clock for the dealers eyes only?

 

NewB2Lexus: I've always done it like you but I've heard people mention weighing fluid then the temperature doesn't matter when changing.

Black16: No set change amount in any manual. There is mention about changing if you tow though. 40-50K is a good interval number.

 

When you change the ATF do you just do a drain and refill? If I remember correctly, a drain and refill actually only changes about 30% of the fluid in the transmission.

 

Correct... one would have to do multiple drain and refills to get a close ratio of complete fluid swap.

This is for a LC 200 and basically the same as GX but if you wanted to go all out you would change the filter and pump the fluid out through the AT cooler.