Vehicle is a 1992 F150 4x4 with a 5 liter engine. Suddenly started shifting hard and then leaked fluid badly out of the inspection hole. I had it towed home. It was able to pull itself up on ramps by revving the engine. I pulled the tranny. Converter still full of fluid. Fluid does not smell burnt.

Questions: Is it common for just a seal to go out on the tranny? If I replace the pump seal, is that just a matter of unbolting the pump and replacing the seal or does the pump take major mechanical work to remove and replace? Should I just replace the seal? I can easily buy a rebuilt pump, is it worth doing that while I am at it? Comments or suggestions are welcome.

SOunds like it went into limp mode, did the OD light flash?
If it doesn't move very well, there is probably more issues than just a seal or pump.