[Tech]

Do you know if the dealer has the latest software in the transmission?
Sounds like it might be a valve body issue.
The Valve body can be replaced on these cars.
That might and might not fix the problem.
Do you know if they disabled the nuetral control function on your car?

 

[Tech]

The nuetral control function can be disabled by software.
Everytime you stop at a light or slow down the car goes into nuetral to help save gas.Sometimes there is a problem with the function and they can disable it and it will fix the problem.

Other times the Valvebody will go bad and have the same complaints as you have.

But there is still the 3rd chance it is in the trans itself.

But the other 2 options are better than the entire trans.

 

[Tech]

They don't replace parts inside the transmission or rebuild them.
They only replace them.