To force a manual transmission into gear without the clutch being fully disengaged or the engine speed properly matched. This action forces the dog teeth on the synchronizer rings to grind against the gear, producing a harsh metallic noise and sending metal shavings into the transmission fluid.
Heard on the job
If you keep rushing the second-gear shift, you'll crunch the synchros and ruin the transmission.
Insider tip
A persistent crunch in just one gear usually means the synchronizer ring for that specific gear is worn out.
Also heard as
- grind