I have rebuilt a couple K46's over the years for customers. Relatively new JD mowers that were worth fixing. Lots of talk on the web about the craptacular K46. Some folks have gotten more life by changing a thicker oil. According to "some guy on the internet" tuff torq ships the trans dry and the mower mfgr installs the fluid they want. Supposedly TT won't warranty the JD trans because they don't use the TT fluid and use a thinner oil. Oddly enough i see more failed K46's on JD mowers than others. Not sure about that because TT specs 3 different oils in different K46 transaxles. One of which is Hy-Gard Hi Vis. I have put 20w-50 in a whining one and it got by for a couple years. Paying a shop to rebuild one, if you can find a shop that can and will do it, will probably cost more than the mower is worth. None of the JD dealers around me will rebuild mower engines or transaxles. They will just replace them. I just finished doing a engine rebuild (hone cylinder, new piston & rings, new valves, etc) on a Kohler CV15 on a JD GT225 that 3 dealers would only replace the engine for big $$$. Told him he would be better off buying a new mower.