2010 Infiniti EX35 Rough shift after transmission rebuild

A few month ago when driving about 40mph, my service engine soon light came on and I had no power when pressing the gas, while the tach went up. Took to auto parts store who read a code of P1772 Low coast brake solenoid valve…
After a week, the light went off and had no symptoms. Took to Aamco who said it needed a rebuild. They replaced TCM, torque converter, valve body, some kind of parts package etc. When finished, I picked it up and immediately noticed a hard shift at 20mph. I took it back, they replaced the valve body again. Still runs the same. They said they do notice it too but they drove it with their diagnostics which showed nothing and with no codes they would have a hard time isolating the problem. They offered me a 3 year 36k warranty. I’m torn between taking it back again and telling them to tear it apart again, or just keep driving it to see what happens. I was hoping to keep the car 3 more years.

Thoughts on what I should do?

Thanks for any input, and Happy Holidays to all!

Make sure the automatic transmission fluid is at the correct level.This is what caused your transmission to behave this way and the CEL to lit.

Thanks for the input but there is no dipstick or filler cap on this model. I should have mentioned it has 86k miles.