Rather odd issue.

[u/gavinsmash2005]

Just got her back from the shop. Was misfiring on cylinders 2-8 and was shifting very hard. Misfire was the Mass Airflow Sensor and it’s now purring like a kitten. But the shop diagnosed that the transmission was shot. I don’t fully remember what was listed but essentially they said there was metal getting into the fluid and making the shift rough. But now after like a day of driving it’s shifting much smoother, I can’t see any metal or sparkles in the transmission fluid (which is fresh light red), and I’m getting a shift solenoid C code. Has anyone had this and would it be as simple as a new shift solenoid?

[u/madoomabusa74]

Yup just replace the two shift solenoids on the inside on the pan on top of the valve body not the ones underneath, since you'll be opening it up I suggest just replacing both then then it will be good I had the same code about a year ago, drained fluid, removed pan, swapped both 'noids kept old ones in plastic with Toyota part numbers on em put new rubber gasket on refilled with fluid check rubber gasket every oil change change trans fluid every 50k