grinding into 4th
Since the issue is only with 4th gear, its likely that the blocker ring on 4th gear is cracked. When the blocker cracks it will spread open when the slider tries to engage to the gear, which doesn't allow the blocker to "syncronize the gear". On a low rpm shift, a cracked blocker may work good enough to allow for a normal shift. It could also simply be that the friction material on the blocker is so worn that it grinds during high rpm shifts.
Otherwise, you could have damaged/broken keys in the 3/4 syncronizer or even the blocker ring could have wear where the blocker engages with the keys allowing it to spin around during higher rpm or more aggressive shifts.
Sounds like its time for a rebuild.
Otherwise, you could have damaged/broken keys in the 3/4 syncronizer or even the blocker ring could have wear where the blocker engages with the keys allowing it to spin around during higher rpm or more aggressive shifts.
Sounds like its time for a rebuild.
