Hi Scotty!
I have a 2017 lexus Nx 200t with 60k miles. Runs great, get all the services done by a private indie shop. About a month ago, I got a drain and fill done on my transmission by a private indie shop that used Toyota ATF WS fluid. The car drives and shifts fine after the fluid change on my normal commute. However when I was driving on the highway from NY to Maryland (four hour drive), a message came up on the dash that said Lexus transmission fluid temperature high, go to dealer. After I pulled over, the sign went away. Sign came back again shortly thereafter so I pulled over again. Then I drove the rest of the way without any issues. No check engine light or any other issues with the car. Took the car to the Lexus dealer who kept the car overnight and said they couldn't find anything wrong with the transmission after running all their diagnostics in the car. They stated the fluid level was correct and did not end up doing any work on the car. Drove again to Maryland last week and the same sign came up again briefly before going away. I will take the car back to the dealer for another diagnostic scan and possibly ask for another transmission fluid drain and fill. Car runs fine without any trouble codes otherwise. No transmission codes on my BlueDriver scanner. What do you think is going on with the transmission? How do I correct this problem?
-Harvey R
It could be that during one of the fluid changes, some junk clogged up the trans cooler which is usually built into the radiator. See if trans fluid lines go into and out of the bottom of the radiator. If so, you should be able to flush out the trans cooler.
