recently purchased a used 2007 mule 4x4 but is missing the front to rear driveshaft, and two front axle driveshafts. Would anyone have these used parts or where to find them ?

 

Ebay, The Mule Man, mostly for used parts. You can try some cycle scrap yards. Lots of new aftermarket stuff on Amazon and there are a bunch of OEM part$ dealers online and they usually have some aftermarket stuff. Partzilla, Adept Powersports just to name a couple. Just Google search.