Thanks for taking time to read through this.This prevents part shifting under heavy load, protecting the spline and holding the oil sealing system integrity together.Д¬onclusion: The addition of a low cost part design at the time of installation or service will provide higher drive system performance, longer component life, and requires no modification of existing components to install. This design locks the nut to the shaft, and bolts the nut to the pulley. If a lock plate nut is used on the transmission output assembly, the whole unit is stronger. (And letвЂ™s face it, itвЂ™s a lot of work to pull the primary drive to fix it) Under heavy use, the spline does wear, the nut does move relative to the pulley or sprocket, the lock plate wears into the corners of the nut, the materials wear into each other as they shift, and the whole thing is loose as a result, even though the nut may still be locked into place on the shaft by the locking compound used in the installation process. The problem with this sytem is that the nut is anchored to the shaft, and the plate is anchored to the pulley, and the whole system relies on the spline to carry the load, fit properly to avoid movement, and never wear. The factory lock plate system is intended to secure the retaining nut by anchoring the plate to the pulley, and using a hex system to hold the nut. This ONLY works when the pulley or sprocket, bearing spacer, output bearing race, and the output gear are all held TIGHTLY together and act as one part under load. The inside seal uses a square cross section seal (Quad Seal) between the bearing spacer and the inner race of the output bearing. This is accomplished by sealing the external diameter of the bearing spacer to the case using the seal visible on the outside of the transmission, behind the pulley or sprocket. The Transmission oil sealing system for the output gear uses an engineered fit between the output gear, output bearing, bearing spacer and the pulley or sprocket to seal the transmission. If they are allowed to move, eventually, they will wear into each other, and the spline will wear loose, or be worn away completely. These two parts are intended to have a tight fit to assure little or no movement between the two parts under load. The drive energy is being transferred through the spline which interlocks the output gear and the pulley or sprocket. There are several good reasons why a firm lock plate nut should be used to secure the drive pulley or sprocket to your transmission. Why use a lock plate nut on my transmission?

Harley transmission sprocket nut