
Originally Posted by
Arfa Brayne
If you know what you're doing, and the box has done over 300,000km it doesn't hurt to throw in a new set of bearings as preventative maintenance.
Based on a box not showing any signs of problem or wear -
Look for wear in the 4th to 3rd and 3rd to 2nd syncro rings, collapsed springs/wear in the selector detent mechanism, and wear on the teeth of the small gear in 5th gear set.
Bearings and seals will take care of the rest.