May have been too much weight on the front axle. Check the fluid. You might need a new set of heavy duty springs in the front, usually needed for plowing.
Clicking and drumming with popping noises are generally associated with the CV joints on the front axles.
Get it up on jackstands, all four wheels at once, and then engage the 4 wheel and lock, with the engine off, the drive belt removed, and the brake off. Grasp each front wheel and roll it back and forth and in complete circles. Listen at each front axle for any noise. It helps to have a buddy grasp one of the rear wheels and add resistance to the drivetrain.
I see this problem quite often when I hunt in Wyoming. A lot of the rich guys that have them for hunting only get snow, ice and water in their boots this time of the year and then let their Mules set all summer long. The joints are full of rust pits come the next Elk season then they click and clack and fail.
I use a grease needle, looks like a large hypodermic, and fit it to my grease gun, then force the needle between the bellows and the axle, and jack my boots full of Hydrotex Parasyn 70 grease after every "wet" hunting trip. I have never lost a CV joint in years of running these things in swamps, mud bogs out duck hunting, the gumbo out west, and even in the salt marshes in Louisiana, and everything else in between.