The some of the OEM clutch Manufactures are Spicer, Carraro, Alto, and perhaps some others. Many use Spicer Clutches, JD uses some Carraro clutches, the Carraro clutches are build different than others and it makes replacing them $$$$. I should mention that no manufacture is flawless, I have an USA made clutch sitting in the shed that the manufacture failed to balance the castings on. I am going to rebuild the worn Spicer that I have for a spare clutch. I put in a TISCO clutch in my tractor and have no worries about it. For me to replace the clutch I have to pull the engine out because its an Industrial and cannot be split like an ag tractor. To get to the clutch takes about 4 hours of work, so a quality clutch is important to me.