Rotary Cutter Noisy gearbox on Landpride rotary cutter

[BravoXray]

They never do. If gears are noisy when new, they only get worse. Gears don't "break in" or you'd have a box full of metal chips.

Is it still under warranty?

Does it sound like this one: Land Pride RCR186 6" 3 Point Hitch Brush Hog Cutter For 54 PTO Tractor For Sale - YouTube

Then you've never seen the wear pattern on a ring and pinion set. The first few hours allows the two gears to "wear in" or establish a contact pattern. Same thing on spur type gears in truck transmissions. Seen it on every one I ever took apart. The amount of metal produced is very small if they wear in properly.

As for whether they get quieter after time, usually not. If they make noise initially, unless there is insufficient, too much lash or an incorrect contact pattern and it is corrected, they will continue to be noisy.

Spur gears are inherently noisier than helical gears, but don't have the need for tapered roller bearings to support the side thrust helical cut gears produce, and so are cheaper to incorporate into gearboxes.