Wow this thread sure went to crap since I posted it!
I did a lot of research when I was looking into this, I am not an engineer or a mechanic but do have experience with auto maintenance.
I do not believe in "lifetime fluid". Yes it can be lifetime fluid when eventually the tranny fails the fluid is also done. I don't care what any engineer or mechanic says, no fluid is lifetime. I can run the same engine oil and my engine will probably go for 100,000 miles without problems but then the engine will die eventually. Would that be called "lifetime" engine oil? Because the oil lasted the whole "life" of the engine. Chevy calls for fluid changes for severe duty, so there is absolutely NO reason why the fluid can't be changed at regular intervals, NONE. If you want to believe in "lifetime" fluid than that is your choice, of coarse the fluid is going to last the lifetime of the tranny, but now you have to wonder what defines the lifetime of the tranny, and if changing the fluid would have extended the life of the tranny.
My 6T70 has a dipstick and a drain plug. It got a fluid change. It will continue to get fluid changes. And I will guarantee that by changing the fluid it will get the most life out of the tranny possible. Changing the fluid isn't going to hurt the transmission, why would chevy put a dipstick on it if the fluid level was so complicated? They wouldn't. Now as far as the engineers that decided they would make the choice for me that I don't need to change the filter, well in my opinion they are very wrong and should be paying for new transmissions when they fail. I could never change my oil filter when I change the oil but eventually it will clog, just like the transmission filter will eventually which will lead to transmission failure. If a filter is needed it should be replacable, period. No engineer should be able to decide that my filter never needs to be changed, why even have a filter then? Basically the engineers are putting a limit to the life of the tranny. If I chose not to do maintenance on my car that is my choice but when an engineer decides for me that a filter that should be changed is not changable that is wrong.
Trannies are the weak links in most vehicles, they need to be serviced to get the most out of them.
In the end we are all responsible for our own vehicles and can decide what we do to them as far as upkeep, unless engineers decide for us. But there is no such thing as lifetime filters and fluid.