I have a '95 with A/T that "slips" when upshifiting (feels as though transmission slips into neutral) - rpms goe sky-high as if I were trying to drive it in neutral. Shifts back into gear and rpms go down when I let off gas. Have 2 theories and am looking for input/suggestions. Theory 1: faulty transmission shifter solonoid. Theory 2: possible crack in forward clutch piston causing disengage. Anybody have any input?

 

Is the slippage occuring only between the 2-3 upshift? My Expedition with a 4R70W trans is now in the shop having the 2-3 shift accumulator valve replaced in order to cure this problem. Part +/- $25. Labor (at a Ford dealer) +/- $250.

As the "slippage" is occuring between gears, it is more accurately described as a "false Neutral".

 

Thanks for the info, PaulC. No, slippage isn't limited to 2-3 upshift. It started out as 3-4 and is now 2-3 and 3-4. I'll check into shift accumulator valve. Thanks again!