If it's an automatic trans, sorry to say but that's what it sounds like. Something in the tranny is acting up.
And DO NOT install a larger fuse. Doing so could fry something like the wiring harness at least, or worse.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.