Those work fine, but there is still a little slop in the diff when you do it. Doc lockers work really well for no slop, or you could go to the tried and true welded diff. Just depends on what trans you have, and what budget you have. My first mower had an 800 series 3/4 axle and that had a welded diff which never failed because there is a bit more welding that can be done, and I have helped guys who want to be competitive with 3/4 transaxle do doc lockers, and other guys run the 3rd gear. They all work pretty well...just depends...
