I'm replacing the transmission torque converter solenoid in my 2007 IS250 with 126k miles, the car first began getting stuck in 3 and 4th gear until suddenly the transmission stop working. My mechanic told me that he is going to change the torque converter solenoid, strainer assy and the oil pan gasket for the transmission. But my big concern is Should I change the transmission fluid or keep the one that is already there?

I have been searching many threads regarding the topic but haven't found someone with a similar problem to my case.

Help me CL Wan Kenobi!

 

So is your question whether or not you should keep the current trans fluid in the trans or flush it? Well, while you have the it half-cracked open, you might as well flush it.