tranny slipping

went out for a little mud action today nothin to hard.cruised up a couple hills and came down a long gravel road to a friends house. while driving up his steep gravel driveway i noticed the tranny was about 2500 rpm's and barely moving .more gas more rpm's no more speed than before.got her home checked the fluid and its dead on the mark of being full.i'm running a 93 xj 4.0 H.O. .also when i put the go pedal to the floor it does not want to shiuft down and when it does it barely gets anymore acceleration.