It began a couple of days ago as I went to work I put my GMC Van into Reverse and it didnt go anywhere until I throttle it hard, and then it started to move. That day on it seemed to be alright after I had it warmed up with no problem until yestersay. I was riding down the road in it seems that I have to push down on the gas peddle more just to get it moving and now it doesnt want to go faster than 35 miles an hour unless I really push down on the gas. It seems when in 3rd gear it acts as if it's in neutral until gasing it. Is it something in the transmission internally missed up or what? Please if anyone can hellp me with this one I would appreciate it very much.