I have '21 FX4 that is in great shape (135k) but starting to get the rough shifts that the 10R80 is known for. What is the best replacement transmission and how do you find a good shop that makes the repair worth the cost? Haven't done a lot of research but did find the Monster transmission as a replacement - my change is not imminent but is definitely going to happen. I really prefer a new transmission over a new truck as I'm close to retirement but also interested in any real world examples yall have that would push me one way or the other.