My 94 explorer has 206000 miles, and it has been doing something very strange to me. When you reach about 55 mph or higher, it's almost like the tranny shifts up into overdrive (the rpms come down to about 2200) and then you cannot accelerate. When you give it more throttle, it just acts really doggy, and if anything, you slow down some. If you let all the way off the gas, and then get back on it, you can accelerate again, or if you floor it, it will downshift, and then you can accelerate again. Is this something to do with the tranny or converter? Thanks.

 

Here are some parameters I am used to. During normal cruise my 94 Explorer with 139,000 miles will shift into overdrive around 55 miles per hour and the rpm will drop to 1600 rpm. Depressing the gas pedal a bit will shift out of overdrive. The only time I recall a subtle difference was when the diaphragm on the vacuum modulator started leaking and the engine was sucking oil out of the transmission. Has the vacuum modulator ever been replaced, if not you might start with the modulator and/or the vacuum line to the modulator.

 

Yes definitely check the modulator, passenger side of tranny......