I have a early 99 f250 super duty 7.3 with the auto trans and I am getting some strange noises from the motor or the transmission. This happens when I am doing freeway speeds from 65 to 80 miles per hour. It sounds like the engine speed is going up and down slightly in about 4 or 5 second intervals but I cant see a change in the tac.
I have had some recent transmission problems about 5000 miles ago, the front seal on the input shaft went bad and pissed out a few quarts and trans temp got a little hot. I have put in the upgraded seal and upgraded the trans cooler to the 6.0 one and flushed the trans and replaced the filter.