It used to be the automatic transmissions were the best most reliable part of most cars especially everything from GM. Now, most brands have transmissions as the weak point in almost every car and truck. Over here in PH they can't repair automatics, especially these new ones, you have to replace the transmission if a fluid and filter change isn't done soon enough or there is something else going on. Ford has a parking lot full of new Ranger Raptors with bad transmissions. One new car we bought shifted way too low in every gear. The dealer had no idea what to do, all they did was check the electronics and said it was OK. I finally got the factory to make them do a pressure check since I thought the valve body was stuck. The valve body was stuck. I suggested they remove it and retorque it in the correct sequence but with 1/2 of the torque applied each time, then change the fluid and filter. Fixed! Years ago I had some Allison and Torqueflite automatics that went over 1million miles each with just normal maintenance. I guess now, newer isn't better like it used to be.