Weird to see all these 4r70s replaced (I know the 4.0 trans is weaker). I change the fluid on mine every 50K miles and it has an external cooler and filter. But with 195K miles it shifts great and doesn't slip at all. Maybe that little bit has made the difference? I'm not easy on it and it's seen a decent amount of towing. Of course we had to bring up the reliability of these... an idler pulley just took a shit. 15 bucks and 30 mins later she's good again.