The K46 in my JD LTR166 I thought was dead, it was bad. This is the 2nd or 3rd time since owning it for past 11 years I had to swap fluid. Hard to get to but I used the oil extractor and got all out I could. I replaced with SuperTech 20W-50 and a little run and it seems to be OK again. I didn't install my deck yet because while it's accessible I'm going to extract the ST and replace with 5W-50 High Performance Lubricants Hydrostatic transmission fluid. Hopefully that will work better and last longer then the Mobil 1 15W-50 it had.30 days warranty
Yeah the K46 in the Craftsman isn't going to last forever and I've also seen cases on online forums where new fluid didn't work. Now, that Craftsman has served me well for 12 years and 155 hours (190 total) so if that happens it owes me nothing.
HPL also has a 20W-50 Hydrostatic fluid if you want for future.