Paragon transmissions use a planetary gear
mechanism to develop reverse rotation. When the gear
box is in forward mode, the clutch
and planetary assembly rotate as one unit and thereís is no noise
. When you shift to reverse the reverse brake band clamps on the outside of the planetary assembly, causing the planet gears to revolve around and rotate the sun gear in the opposite direction, giving you reverse gear. This gear motion of the planetary gears causes the noise
that you hear when in reverse gear.
If the prop shaft slowly rotates when in neutral it could be something as simple as oil
drag on the clutch
plates, and thatís nothing to worry about, especially if it has done it since new. Make sure you are using the correct oil, as oil that is too heavy can cause this drag.
If the rotation is more recent, or is very strong ( you canít stop the rotation by lying your hand lightly on the shaft) itís possible that there are some warped clutch plates, or the clutch plate separation spring has failed, and you might want to have that looked at.