Inspect the reverse idler gear shaft/holder for wear and damage.

Inspect the reverse selector gear teeth chamfers, and inspect the engagement teeth chamfers of the third shaft reverse gear and the reverse selector hub. Replace the reverse gears and the reverse selector if they are worn or damaged. If the transmission makes clicking, grinding, or whirring noises, also replace the third shaft 4th gear, the reverse idler gear, the mainshaft 3rd gear, and the countershaft 2nd gear.