Ok I have looked on here for something similar, but couldn't find it. I have a 2006 F-250 with about 112,000 miles. About one month ago the truck was doing the same thing where it wouldn't shift until about 2500 rpm. I always baby the truck so I wasn't driving it hard and one day shifting from 2nd to 3rd it just went straight to nothing, just like it was in neutral and that was it. We took it to a mechanic and he said the shifting solenoid came unplugged because the clip was broken on it. He put a new harness, changed the oil and filters and that seemed to fix the problem for a day. Now it shifts super high like 2500 rpm still and also its, i'm guessing you would call it, surging. It vibrates and everything sounding like the motor is missing when it's trying to shift. I don't know what the problem could be. Maybe the torque converter?
Thanks for looking
Ok new thing just heard. When ever your coming to a slow stop you can feel and hear a little clunk sound coming from the tranny....
So when ever the truck gets good and hot it seems to run fine and shift fine.... It takes it about 30 min to get running right. Sorry to keep adding stuff. Also noticed a little bit of a rough idle when in park and rev'd up, not bad but you can feel it a little bit.