Yup that's what happens , I lost fifth gear just driving , just gone , no grinding , nothing , took it apart and the nut had just backed off and so had the gear , they where just hanging on the shaft , it cost me about $375. 00 to $400. 00 doing the repair my self including tools & oil , oil was $54. 00 gal , the best way to repair would be with a new fully splinned output shaft from standard transmission or from Quad 4x4 , standard has the prices on their web site and quad 4x4 seems to have most of the tools , or go with a remanufactured transmission with the new updates , do a search you will find out nobody has good luck with just the nut repair , only one member , but he drilled into the main shaft to give the set screws something to hold onto . good luck , Dick R