I have a 93 ford f150 driving down the road it dropes gears i changed fluid and filter it did not

I have a 93 ford f150 driving down the road it dropes gears i changed fluid and filter it did not help?

Internal issue. Start by checking the fluid level and condition. Look for contamination of clutch material or metal (which you may not see now because you serviced it), take the valve body out and make sure all of the valves move properly when you push on them. Hook up a trans gauge to check line pressure.