I have a 1994 Nissan Pathfinder 4wd auto. I was driving it the mud and noticed that any foward moving gears didn’t engage and I was stuck with reverse. Then while trying to get out of the mud in reverse I heard a click and then reverse stopped. The car runs fine I just can’t drive. Nor 2wd or 4wd works, or any gears. I don’t really know what has happened but I think I’ve done a transmission. I’ve topped the transmission oil up and all but still nothing. Is there any way I can fix this? Or what could I do?