In today's Manufacturer World No Automotive Company makes most of their parts. They come from many different manufacturers that specializes in certain types of parts. Even major auto manufacturers had difficulty in completing cars and trucks due to part shortages.
You could of taken starter off, look up local company that Rebuilds Starters & Generators for Trucks in your area. They could probably Rebuild Yours for less money.
You must understand it will take a few years for Company and Dealership to stock up extra supplies of parts. Diesel Engines Need Great Amount Of Cranking Amps In Battery.
I suggest getting a better battery than stock with highest cranking amps for size and terminals placement. Replacement of battery: Interstate Battery Company Dealership should be able. This is a four wheel drive vehicle but I seen many videos treating as it is Amphibious Vehicle. Abuse Of Any Vehicle Will Cause Damage. Water, Mud left around engine, starter, etc. Causing Damage, Excessive Heat Build Up On Engine, Starter and if Mud Builds Up on Radiator may cause engine to overheat and maybe blow up. Buy A Power Washer, on cold engine, use fine nozzle, clean everything in, under, & every nook on vehicle soon after wheeling. You Roxor will appreciate your kindness.