Transmission issue?

Hi,

You are correct. The torque converter is what allows the vehicle to be stopped and remain in gear. To a degree, you may notice the downshift, but it shouldn't be abrupt. Also, you could try an additive designed to improve shifting, but it may not help.

What really should be done is this. The can-bus should be scanned to see if there are any diagnostic trouble codes stored. CAN stands for controller area network. Basically, all the different computers/modules are tied together via a few wires, and they communicate with each other. This type of scan will identify codes regardless of the module storing them.

Here is a link showing how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know if you have already tried having that done. Also, an additive won't hurt. It may be a good idea to try. Just make sure to get a good product.,

Let me know.

Take care,

Joe