Why is my manual transmission grinding when shifting? Transmission is very complex parts that is why when there is trouble it is very hard to diagnose without looking at the actual transmission, the diagnosis mention on this article is just a possibility unless the actual transmission is inspected.
If there is grinding on the transmission when shifting to one particular forward gear the possible reason is that there is a problem with the synchronizer of that particular gear. What is inside the transmission is a device called the synchronizer, the purpose of the synchronizer is to bring the rotating shafts/gears together at the same speed for smooth shifting. If the synchronizer is faulty a grinding sound occurs and shifting will become impossible for that particular gear.
But if the grinding occurs only at first gear just after shifting from a stop and not during downshifting the possible reason is that there is too much clutch pedal “free play”. Free play is the distance of the clutch pedal movement before the clutch begin to disengage. If there is too much pedal free play even when the clutch pedal is press all the way down, the clutch is still not fully disengaged and will results to grinding sound when shifting into first gear.
Free Car Diagnostic Recommendations
Seek the help of the mechanic specialized in transmission repair to inspect the transmission, if the mechanic recommends tearing down the transmission do not agree without seeking for a second opinion. The problem may be solved by simply adjusting the clutch pedal free play, mention this to the mechanic.