Good call. I checked it when I got home and it was about 1/4" below the bottom mark of the "C" section so it's about 1-2 qts low. I'll get 2 qts of bulk ATF+4 from work tomorrow and add to it when I get home. Makes sense. The truck has always seemed sluggish and got poor MPG since I changed the trans fluid. Low fluid pressure or slippage could explain why. I just thought it was part of owning a power hogging automatic.