If you stay with John Deere and purchase new, I believe the X380 is the start of the K58 transmissions, which right now with their sales will set you back just about $4K with taxes. You can also get a Cub Cadet GT50 with a K58 for around $3K with tax any time. Difference in the two is likely the more robust chassis, Kawasaki FS engine and better warranty on the Deere. The Cub Cadet has a more powerful engine, slightly larger deck and a very nice, responsive steering setup. Other than those, you can try to find a still new, last year's model Husqvarna GT48DXLS which has the K66 with Diff Lock and those run $3K plus tax, but the build quality of the machine will not be near the Cub let alone the Deere. A drop in tranny will set you back hundreds or more if you are buying a new one. Its up to you if you want to put that much money into an older machine, or sell it for parts and put that money into a new rider that can do everything that you need it to do. Good Luck.