tranny trouble

got a 93 xj ax15. was out wheeling a while ago in the snow. got a little stuck so i tried to revers out of where i was. after a little while while in reverse it started making a knocking sound. but i kept going. then normal driving it still made the slight knocking sound in reverse, clutch depressed or not if moving in reverse it would make the noise. then was backing out of a parking stall and it just locked up in reverse. couldnt get it out of reverse no matter how hard i pushed the lever. jeep on or off. couldnt get the transfer casse to shift into neutral either then. so i just gave it alot of gas and it made a pop noise and then i drove home in 1st-4th gear. tried putting it in reverse and same thing happened. so i've drove it a while now just 1-4 and never backing up. i need a whole new tranny dont i?