My truck started shuttering when slowing down and after a few days would shut off when put into drive. Threw a p0743 I think was the name. Whatever the code number was it was the tcc solenoid. Did a fluid change and replaced the tcc. Now from what I’ve heard is if the little yellow plug was in the trans pan then that means no one has ever changed the fluid in it? Is this true?

 

It's true unless a) they left it in the pan for whatever reason or b) they used an exchange machine without dropping the pan.