Confused over Strange Shifts

[Petey]

Over the last few weeks, I think, was feeling very harsh 1-2 shifts, softer 2-3, and normal 3-4.

I decided to check the fluid and noticed that it was at the full cold line after I had driven for a bit (less than 20 more than 5). I decided to add only a 1/4 of a qt in case I was reading it wrong. This time I drove for well over 100 miles up and down some good grades and checked again (it was still around the full cold line). This time I added the rest of the QT. Now its reading just below the Low hot line so I need to get more and add.

The thing still has hard shifts so for the heck of it I switched the ECU back to the factory one without the PCM tune. It shifts smooth as silk now.

I am confused because the Tune has been in there for 7+ years and 50K+ miles. It did have firmer shifts but I don't remember ones like this.

The Fluid:
The dealer did a flush at 50K and it now has 91K. I know I am bad and don't check the fluid religiously, but its not leaking it.

Where did 1+ qt of fluid go in 40K?

 

[Sparky]

It has to be leaking someplace, because it can't disappear otherwise. Or, it was never fully filled to the line to begin with.

 

[littleblazer]

If you have torque or the likes check the actual temperature of the transmission. In the winter mine only creeps into the 140s so it reads low but a bit above the cold line. Once it hits upper 160s it usually ends up in the hot and then 180s is usually a bit over full. Kind of weird but it does swing alot.