I have a 95 ford F-150 4x4 brand new trans. I drive down the road it shifts out fine till you get to 50mph or better and it seems like its jumping back and forth between gears anyone have any suggestions on what it could be or what to try. I've replaced computer rebuilt trans fluid level is where it should b im stumped what should i try next?

 

Sounds like bad wires going into the plug that plugs into the transmission on the passenger side.

 

Is it on stock rims and tires?
What engine?

 

What transmission do you have also?

 

Mine does this around. 40. Rpms go up... Then go down...then go up...then go down. There is a tsb on the transmission wiring harness. As mentioned by subford Havent looked at mine yet. Mines e4od. Soon to be manual.