If a drain and fill series doesn’t help you pretty much have to decide between a valve body job or a trans swap.

Also a high end scanner mit pick up TCM codes for guidance even if the check engine light is off

- Not good, but great since you can consider that a flushing fluid. Get a case of this JWS 3309 Full Synthetic ASAP before it goes up. Can use the MVS link to help with this website at no cost to you. Additives in the fluid matter! https://www.amazon.com/HAVOLINE-226536481-12pk-Synthetic-Multi-Vehic...