What typically indicates worn blocking rings in a five speed synchronized transmission?

Worn blocking rings in a five-speed synchronized transmission typically present a grinding noise when shifting gears. This is because the synchronization mechanism relies on these blocking rings to engage smoothly and match the speeds of the gears involved during shifting. When the rings are worn, they cannot effectively synchronize the gear speeds, leading to a mismatch that causes grinding sounds as the gears attempt to engage. This audio feedback typically indicates that the transmission is not functioning properly due to the wear on the components meant to facilitate seamless gear changes.