Fifth wheels need lubricant, but too much grease can interfere with the locking mechanism when it thickens in winter.
Keep your Diesel Fuel from Freezing this Winter
Preventing fuel freeze-ups in heavy-duty diesel trucks is much easier than fixing the problem after it happens. Stay on top of your fuel tank maintenance and pay close attention to what you put into the tank; these are the only sure-fire solutions for preventing cold-weather failures.