2007 ES 350 Torque Converter
 

My '07 ES350 needs a torque converter. (I actually had a retired mechanic in the car that thought this might be the issue. While driving it seemed to go into neutral, no gearing or power. When going from park to drive it went into gear, but if gas was applied the engine just raps up, rpm goes up.) The Lexus part is $1300 and carries a warranty, but the reman part at AutoZone is $203. I know there wouldn't be a warranty, but would the AZ part be okay?

Any codes? Some fail safe conditions have that same symptoms.

They did run codes. After filtering the transmission fluid and finding metal shavings, now the transmission needs to be replaced. Love the car and just did new tires and front brakes. Hmmmm, wondering if $6,625 is more than the car is worth. Its in excellent condition.

I think for this sort of transmission problem(s) you experience, you need to have a lot of confidence in the transmission shop or dealer that is giving you the advice. There are a lot of shady actors out there...

So much this.. Also, ask to be present when they drop the pan and empty the filter so you can see with your own eye the color/smell of the fluid and inspect the pan/magnets for shavings. That material is important to take photos of as evidence when you take it for second/third opinions

That is probably too much money to invest in the car. It is 14 years old! Sometimes you just need to cut your losses and move on to another vehicle.
Get pricing on a used or rebuilt transmission from a few different places.
You never said how many miles it has. That is a big factor in deciding whether to go forward.
Also if the torque converter is shot you cannot just replace it and hope that works without further diagnostics as the solenoids are probably also shot as will be the clutch packs etc.
However, it appears a sure thing your transmission is shot.
I would look for a used low mileage one. Then change the fluid during the installation.