Scotty, after a 500 mi round trip, my Buick Regal's automatic transmission began to slip about 475miles into the trip or roughly 25mi from returning back home. It was especially more noticeable after getting off the interstate. In between 2nd and 3rd gear, the engine's RPMs would rise up to ~3.5k to ~4.5k RPM soon after 2nd gear before jerking into 3rd gear. Unfortunately, I have not followed the recommended automatic transmission fluid change interval. My car has 69,715 mi. (just under the Powertrain Limited Warranty that ends at 70kmi!) and I was supposed to change the fluid at 45k mi. This is the newest car I've ever had and I've made the mistake of not following the recommendations on my owner's service manual. I did not drive the vehicle the next day after my round trip but I did turn the car on to check the automatic transmission fluid level. The fluid level was on the MIN reading on the dipstick, looked red/not dirty, and did not smell burnt in any way. I dropped it off at the dealership today and I will await their diagnosis results tomorrow. I've viewed many of your videos and I know a question I should ask is if all electrical components have been ruled out first and if there are any misfire codes from the engine (both achieved through retrieving computer codes from the onboard computers). My question is as follows: In your experience, how likely is it that I've caused major internal damage to the automatic transmission by not adhering to the recommended flush interval? I use the vehicle very gently for my 90 mi. daily commute. All highway. I have a feeling this is the result I'm going to get from the diagnosis and I would really appreciate your expertise on this issue. Thank you.