4R75W transmission missing fourth gear and overdrive?

4R75W automatic transmission in the truck listed above King Ranch hard shifted (really hard) while accelerating out of a curve. It sputtered a little. The overdrive light came on and the reading on the dash said that the overdrive had malfunctioned. Other than that, it drove fine until I made it the other two miles home. Checked and the fluid was low, so I added fluid. The next day the reverse had gone out. Neutral was pulling forward and my overdrive was still out. Now reverse and neutral are back to normal but it slips into neutral as soon as fourth gear starts to grab.