How to add the snow textures you go to C:\Program Files (x86)\Steam\steamapps\common\Farming Simulator 17\data\shaders And save the vehicleShader somewhere so you have it to put back, or just download it from from my site. Now drop the modded vehicleShader in to replace it and now you have snow to show on your ingame equipment.
Use the same vehicleShader in your mods just rename if need to and replace the dirtShader or vehicleShader file.
If you want snow right now on your equipment buy the equipment then save the game, then go to your saved game in C:\Users\Harris\Documents\My Games\FarmingSimulator2017 and then savegame(1)to (20) whatever your game is saved under. open the saved game find vehicles.xml the you will see your equipment data/vehicles/steerable/jcb/jcb435s.xml then at the end of the line you will see dirtAmount="0" change the 0 to a 1 now that one is fully snowed on!
Not sure but, A tip to play mp you all will need the modded vehicleShader in game so the game will start up. I have not did much testing on this in fs 17 it did work in fs 15 tho.