Getting rid of my blazer for this was the best thing i ever did but i have a question. I just turned 49k miles and the tranny shifts to overdrive at 45mph almost no matter how u accelerate. say you are crusin down the highway at 60mph, let off the gas a second and then get back on the gas and the engine speed will increase and a second later will slip back down to whatever rpm it was at. sorry but i am haveing a hard time explaining this but if u have an idea let me know

Ok , I think I know what you mean. My 00' XJ with 93K+ does the same thing, has done it for as long as I can remember. Fluid is good, not burnt. I think it has something to do with the torque convertor locking up. I would have to say its normal, but it couldn't hurt to change the tranny fluid.